eg. Voldemort’s problem wasn’t that he tried to extend his life, it’s that he was willing to sacrifice any number of other people in order to do so, a net increase in death overall.
Harry’s virtue wasn’t in being willing to die, it was in being willing to die in order to save others, a net reduction in death overall.
Voldemort’s problem in the original is absolutely that he tries to extend his life. It’s only due to the constraints of the story that life-extending stuff is usually inherently bad, but Dumbledore basically says that he’s evil for his belief is nothing is worse than death.
Rowling is a Protestant, isn't she?
This is sort of intertwingled though: Rowling writes that Voldemort is bad for dodging death, but she also sets it up so that the only way to dodge death is to be bad. This isn’t unusual, the dodgy Pirates of the Caribbean sequel with the fountain of youth did the exact same thing: you can only save your own life if you are willing to kill someone else, which defeats the entire purpose.
You can’t really debate the antideath issue from within the prodeath framing.
The Philosopher’s stone provides indefinite life extension with no loss of life, yet Flammel gave it up easily, and so did everyone else. Unicorn blood is breakable via using dying unicorns.
“Death is actually good” seems to be an axiom as baked into the wizard society as “we and the muggles have nothing to learn from each other”, and the former is not plausibly argued against in the context of the story.
The reason “you want 1000 Holocausts” and “you want my mother to die” are good responses are because they are an emotional whiplash to an inherently emotional argument (death is actually good because it just seems right yano) wrapped to seem as if it was the reasonable and logical position. When people try making those, I’ll examine their arguments. Until then, it’s asking why they believe Hitler didn’t go far enough.