Who wouldn't select a part of the population they find unsaveable, say evil genocidal billionaires, and sacrifice them for extending their own lifespan + improving how they believe the world should be? Win-win.
I feel sad that you seemingly have met more people who lack compassion and empathy than ones who have it. Personally, I don't know (or "hang out" rather maybe) many people who'd sacrifice anyone's life just to live a day longer, and I don't think that's a useful default view to have of people, most people I've met don't want to hurt others. Most people will hurt others if they can avoid getting hurt themselves by doing so, but that doesn't mean those same people would sacrifice someone's life to get another day.
I'm not a nihilist and I do eat meat. I think we should minimize suffering to others. But I can see how anybody could be conditioned to think otherwise. It's not some inherent human instinct to want to preserve others' lives. We've had to develop that instinct culturally.
So who am I to judge? I have impurities in my heart because I dislike people who cause harm. Best wait for the saints to weigh in.