If we domesticate the majority of the planet nothing substantial will evolve without us controlling it. We have replaced a large percentage of wild organic biomass with us and our pets and cattle and farms.
'it's nothing compared to an asteroid impact' is just the elaboration of 'humans can't impact climate lol' or 'obviously you don't even care about the heat death of the universe'. While we shouldn't paralyse ourselves with existential guilt, evoking apocalyptic scenarios in a policy discussion is usually intended to derail discussion and prevent the emergence of consensus, ime.