I think some of the confusion here might be that this comic is specifically referencing booting out bigots and their apologists.

if someone is willing to argue in bad faith (in this case, specifically bigots), there is no reason to listen to that or anything else they have to say since they've shown they are willing to argue in bad faith at all. I also think anyone who is an apologist of them is also not worth listening to because they are in bad faith by proxy.

that being said, it's perfectly okay to have people arguing in good faith while coming to different conclusions. there can be disagreement and that is healthy as you've said.

such as whether or not you should block people who disagree with you.

I don't think anyone was making the argument to block everyone who disagrees with you. If someone wants to do a social intrigue game in DND I'm going to think that's not the best tool for the job, but I'm not going to block them.

If someone's like "women shouldn't be allowed to vote" then that's a whole different kind of disagreement.

My point is that you can’t arrive at what is right without knowing what is wrong and you can’t know what is wrong if you block everyone who disagrees with you.

I don't know if that's true? I don't need to see every variation of racist argument to identify racism is bad. You don't need to know the full set of possibilities to pick a good one. Like, you probably have reasonable interactions with dogs on the street and never considered going on all fours and aggressively pissing and howling before.

This only applies though if the bigot or their apologist is willing to have an honest discussion with good intentions. The problem with tolerating them is that they do not have any respect for truth, or in having an honest discussion. Engaging with that is beyond pointless as the best it serves is to show people that already understand it to be bad that it is bad. And at worst it will confuse someone who doesn't understand or reason well into siding with bigotry.

All this discussion of "well people should know and be able to reason" falls flat when you look at examples around the world where intolerant bigots were tolerated. The US and Germany are two examples I can think of off the top of my head. The US has a felon, fascist, wannabe dictator as one option and he has an honest chance of winning. Then in Germany they are having essentially a resurgence of the Nazi party in AfD and it's been gaining traction, particularly in eastern states from what I've read.

Bigotry and hatred don't need a platform. They do fine on their own. Giving them shelter only creates issues. You don't need to see their arguments because their arguments don't come from reason but from spite and they have no intention of fair engagement.