Because they're caused by changes to the ecosystem, and some of those changes are going to kill us off.

They also cause further changes to the ecosystem in weird complex feedback loops, which will also kill us off.

They'll also collapse some food chains which will kill off many humans.

I see your point. If we can survive on Mars without bringing along a huge amount of biodiversity then we can survive on Earth after turning it into Mars. Awesome. But maybe we can't survive on Mars after all.

> We don't live off the wild.

You don't eat fish? You don't eat food that requires pollinators?

I think all the fish I eat is farmed... Now I'm curious, because that's a partial counterpoint. Doesn't defeat the message, but it's certainly a gap.