I don't think it's fair to draw this comparison on either end as this concerns relationships that are extremely contextualized and subject to change (human to nonhuman animal and human to human.) What constitutes suffering is highly debatable, we're not dealing with faulty RAM sticks that make the execution of operations unreliable.
The impossibility of creating clear and objective frameworks/rationality based decision-making has been a tool time and time again for repression. It starts with putting grandma out of what we or anyone who is not grandma considers to be her misery, then we go on to NICU children in dire or uncertain circumstances or individuals who can't communicate or contribute to society, and so on.
https://en.wikipedia.org/wiki/Aktion_T4
cmd+f "Gnadentod"
Don't get me wrong, I am not against people choosing on their own accord to go. Even if I think there are caveats with that because I don't consider people to ever be able to completely grasp their decisions and make decisions autonomously. We're after all limited creatures. I suppose in cases of extreme disease assisted suicide non the less represents a rational personal choice.
What keeps me from supporting an institution such as MAiD is how economic pressures can greatly affect the question of who dies and who dies when. If a person has the resources to pass in a comfortable environment, like a nice home in a calm part of town, they will consider assisted suicide much later in their trajectory than the person who has hardly any next of kin and no financial resources to install, say, the necessary aids at home. The former individual does not spend their last days in a stressful hospital environment. Of all examples I could give this is probably in the category of least extreme. As long as this contradictory aspect exists MAiD and everything like it will fail to live up to promises. Off the top of my dome I'm not able to name any regions where this would not be the case, even Sweden or Switzerland have dirt-poor strata that would be negatively affected.
I would carefully disagree here. Would freedom not mean that the recipient of medical care gets to ultimately decide? Considering the state of the world, free world is a contradiction in adjectives. Especially here. I know this is a pedantic ask with it's scope, but I'm trying to nudge you away from a certain centrisms.