no species in the world is capable of caring once they’re extinct

This doesn’t mean it’s fine if we go extinct.

I don’t see why it’s not “fine”. If everything was fine to the individuals of the species up to that point and then there just wasn’t more of those individuals coming into existence, where’s the problem exactly?

If you could snap your fingers and cause all pigs to die instantly, would you do it?

Interesting question. Since I think negative utilitarianism matches my moral intuitions pretty well I’d say there’s no problem in the benevolent world-exploder scenario. If this thought experiment happens in a vacuum where it wouldn’t have any consequences for any other individuals, and the dying was instant in a way that none of the pigs could experience anything about the event, then I guess there’s no problem if the pigs cease to exist. And I’d say the same applies to us: if there’s nobody to experience anything negative about an event at any point of time, why would it happening be negative? Please tell me if you have some argument against this scenario.