Every single militant vegan has thought it through, that's why they do what they do.

A lot of melanin-deficient people today think, "Malcolm X was too extreme and alienated people, MLK Jr. was inspirational and gentle, and that's why he succeeded." But this is a historical anachronism. MLK Jr. was the "militant activist". During his life MLK Jr. was one of the most hated men alive, whose tactics specifically were criticized as alienating the public.

A major interfaith council released a "Call to Unity" saying racism was important address, but publicly shaming MLK Jr. on his tactics:

....we are now confronted by a series of demonstrations by some of our Negro citizens, directed and led in part by outsiders. ... we are convinced that these demonstrations are unwise and untimely.

MLK Jr. specifically responded to such criticism in his "Letter from Birmingham Jail", where he specifically defends his "militancy" and defends a theory on which the unpleasant tension it creates is in fact necessary strategically to justice to be achieved:

In any nonviolent campaign there are four basic steps: collection of the facts to determine whether injustices exist; negotiation; self purification; and direct action. We have gone through all these steps in Birmingham ...

You may well ask: "Why direct action? Why sit ins, marches and so forth? Isn't negotiation a better path?" You are quite right in calling for negotiation. Indeed, this is the very purpose of direct action. Nonviolent direct action seeks to create such a crisis and foster such a tension that a community which has constantly refused to negotiate is forced to confront the issue. It seeks so to dramatize the issue that it can no longer be ignored. My citing the creation of tension as part of the work of the nonviolent resister may sound rather shocking. But I must confess that I am not afraid of the word "tension." I have earnestly opposed violent tension, but there is a type of constructive, nonviolent tension which is necessary for growth. Just as Socrates felt that it was necessary to create a tension in the mind so that individuals could rise from the bondage of myths and half truths to the unfettered realm of creative analysis and objective appraisal, so must we see the need for nonviolent gadflies to create the kind of tension in society that will help men rise from the dark depths of prejudice and racism to the majestic heights of understanding and brotherhood. ...

indeed, his most intense criticism is lobbied towards the "moderate" who "agrees with you in the goal you seek":

I must confess that over the past few years I have been gravely disappointed with the white moderate. I have almost reached the regrettable conclusion that the Negro's great stumbling block in his stride toward freedom is not the White Citizen's Counciler or the Ku Klux Klanner, but the white moderate, who is more devoted to "order" than to justice; who prefers a negative peace which is the absence of tension to a positive peace which is the presence of justice; who constantly says: "I agree with you in the goal you seek, but I cannot agree with your methods of direct action"; who paternalistically believes he can set the timetable for another man's freedom; who lives by a mythical concept of time and who constantly advises the Negro to wait for a "more convenient season." Shallow understanding from people of good will is more frustrating than absolute misunderstanding from people of ill will. Lukewarm acceptance is much more bewildering than outright rejection.

Fundamentally, if vegans do not actively challenge this perverse system which normalizes immense violence, they are implicitly normalizing it. When people see injustice and cooly ignore it, suppressing their outrage, saving it perhaps for their deathbed or another century, the general public continues as normal, perceiving nothing wrong, and maintaining their blindspots as no gadfly dares disturb their peace.

When grave injustice exists, people must act as if it is so. When Timmy is stuck in the well, do you saunter on your way, talk in a mild tone, and bother not the passersby? Do you dine with the fiend who pushed him in?

As a matter of fact, people hem and haw and raise stinks and chaos about things 1/100th as consequential as par for the course. A verbal slight using slurs can justify shunning and cancelling. A person who removes someone from their wedding party may likely lose a friend for life. People get in fights over sports teams, and while we view it as idiocy, we still "understand". Burn an American flag and you are liable to be fired from your job or clocked in the face. A career can end from kneeling during the national anthem. Casually throw a plastic bottle on the ground, and raise the intense ire of many of those leftists who happily chomp on bodies. Let's not even get into religious "blasphemy" which can lead to consequences up to and including death.

"Have you hurr'd and durr'd and considered why you don't donate all your money to starving children? We all hurr and durr and cause negative things to happen. Can't end all harm? Then we're not really obligated to end any harm! C'est la vie, you do you champ, and I'll do me. I'll hit my toddler one less time this week to placate you, so you can focus your energy elsewhere. We all have our pet causes, let's give each other due consideration."

The problem with this style of argument is that it ignores a vast asymmetry. Vegans do not travel en masse to help Koni capture new child soldiers. They generally do not travel to Uganda and convince people to put gay people to death. They do not generally own ExxonMobil and dump millions of gallons of oil into the ocean. Vegans are (with rare exceptions) not actively contributing to the harm which other movements are trying to address.

White vegans do not generally go to anti-racist activists and glowingly brag about how they have "reduced" the number of racial slurs they use, nor do male vegans generally go to feminists and gloat about how they "seek consent most of the time".

Meanwhile, members of these other movements frequently contribute personally in immense ways to the suffering vegans are trying to address, prioritizing their own convenience, taste pleasure, and habits over the lives and bodies of others. For Christ's sake, the ASPCA, of all organizations, has held "BBQ Fundraisers", paying for some animals to endure miserable lives and have their throats cut, so that other animals can find someone to cuddle and care for them.

Everyone is hypocritical to some degree, but Lord Buddha man take the log out of your own eye before you shoot the spec of dust out of the other man's eye with your arrow of criticism. The situation is not the same.

And moreover, unlike other issues, such as "peace in the middle east", there are not really legitimate competing strategies to achieve it. People argue over one-state, two-state, this strategy over than strategy, get Saudi Arabia involved or not, etc. Gradual disarming, or peace through strength? Maybe you have good arguments for and against some of these strategies, but reasonable people who are not trying to annihilate other side and desire peaceful and prosperous coexistence have competing views.

For veganism, there is no such legitimate competing view. "I'll rip the wings off of half as many chickens in the coming year" is instantly met with, "Why not rip the wings off of zero chickens in the coming year?" People who argue for military build up, such as Sun Tzu, say: one can avoid death and destruction of war through a quick, decisive victory through overwhelming strength. More guns and soldiers = less death and destruction? Apparently it may be so, according to very smart and seasoned people. An argument about the morality of actions in war is bound to encounter complexity pulling you in opposing directions. Should the U.S. stop sending arms to Ukraine, end the war, end the slaughter, concede the fight, save hundreds of thousands of lives at the expense of independence? You will never find any such argument for ripping the wings off of a large number of chickens.

Thus, while anyone arguing for or against arms shipments to Ukraine (or similar international politics / war issues) must humble themselves that the greatest and most insightful minds have all gotten such issues wrong in hindsight, vegans need not worry that, in hindsight, perhaps those animals' bodies really did need to be cut up, and those baby cows really did need to be taken from their mothers for your celebratory dinner. It's not a serious concern. This gives vegans a sense of moral clarity on their issue, which most other issues lack. This allows, justifies, and in fact requires "absolutism", because it is not a "zero sum game", it is not a "balance of compelling and competing interests and strategies", it is a clear as day black-and-white issue with almost no complications in ordinary practice.

You bring up Peter Singer, but only a small minority of vegans adopt his utilitarian view. Peter Singer does not properly address the epistemic uncertainty concerns, such as "What if I give food aid, and then the local farmers go out of business destabilizing their food system, and their are more starving children a decade from now?" Or other concerns about societal organization, "What if my internationalist aid intervention disrupts natural community development, creating a lopsided dependency in which American hegemony becomes necessary for basic needs, enabling kleptocratic political systems?" Many people can and do criticize people building schools and hospitals (if those people are missionaries). Libertarians, while often myopic and wrong, at least believe themselves that suffering would be reduced overall by cutting social programs. It is impossible to make such a case in favor of the way humans interact with non-human animals.