You're getting some flak for your comment, and I guess I'm responding because I don't think you deserve it, so I'm willing to take flak too because the idea is pretty on point, at least in a tangential sort of way.
There is nothing particularly special or sacred about humanity other than that we happen to belong to that group. If we die out, we die out. The universe goes on just as it will after you as an individual perish, just as it has for everyone who came before you, every species that did, even the stars that went nova creating the elements necessary for you to exist. And whether by the heat death of the universe or simply the inevitability of minuscule probabilities occurring on an infinite timeline, our species is doomed anyway.
Should we care about the possibility of human extinction? Absolutely. But should we be willing to go to even the most extreme lengths, say by wiping out the rest of life on earth, to preserve it? I don't think so. I don't believe that ensuring your survival by contributing to creating a world you don't want to live in is a meaningful exercise.
Like I said, this is a bit tangential since as far as I know no one is suggesting atrocities as a solution to the many threats we face, I just see this idea of human survival as being the highest priority in the universe often enough to want to offer a dissenting opinion.