Imagine that I'm a pal who explained the modern analogous position to you. I tell you that I think our prisons are inhumane, and the death penalty is problematic. I know a guy who beat up 3 cops, a teacher and some kids and drugged them so they forgot what happened when they interrupted him slaughtering some horses, but I don't report him, and in fact helped him cover up his crimes because of my belief. We still buds?

Setting that aside I'm not clear at all on why Harry would still have a problem with the Azkaban/death penalty. Earlier, sure, it made sense, but now that he's declared himself the Vanquisher of Death he just seems confused.

Suffering is certainly bad, but Harry's cool with False Memory charms, and those can negate suffering. The time lost becomes the issue, and Harry intends that folks shall live forever.

I mean, he's going to conquer death, right? Not only that, he's going to resurrect Hermione, who is dead and whose body is gone presumably by now decayed. So he's confident that he will be able to resurrect someone based on, effectively, name and description. Surely he doesn't think his abilities as a researcher are terribly singular, never to be duplicated.

I mean, if he might in theory do it then its ultimately doable, then someday it'll be done, and all will rise.

So.what matter then, when precisely any given individual dies, so long as it does not alter this future? Worst case scenario. Quirrel goes to Azkaban for a few months before his disease overcomes him, and dies a howling deranged lunatic. Later on he's resurrected, false memory charms fix his trauma and bob's your uncle.