If you take an honest look at the situation and decide that trying to save us isn't what you want to do with your time, then I personally think: fair play to you. That's everyone's own choice to make.
On this specific issue though you're probably going to get increasing push back as the people who decide in favor of our continue existence come to consider apathy and nihilism as a problem that's directly hurting the cause.
Honest question: have you considered still wishing the end upon us and all, but just doing it on a more personal, private level?
Second point: If you actually do care about animals, you'd be better off trying to control the outcome rather than wishing a vague end to us. If we vanished overnight, we'd stop accelerating through the current mass extinction (assuming we haven't already crossed a tipping point), but that is not likely.
We're probably going to stick around a while longer, and are on course for ~4 degrees atm, which is going to fuck up loads more ecosystems and their inhabitants than we strictly have to.
(, Mon 2 Dec 2019, 18:31, Reply)