By that logic anything which kills mass population is "not so bad". Why not just bomb cities. Infact if you read it as a response to "world wars", though not intended, that way of thinking justify that.
It depends on your view of the world I guess. In my view, humans are not special. We have no inherent right to live on this planet compared to other animals. Why should we not die off and let other creatures live? Only selfishness (and our cognitive ability to have it), enables; I want to live. Humans are not special (except for currently being at the top of the food-chain). We have reached our biological population limit. And it needs to go down. And even if it goes to zero, the universe won't care. We are just another species and we are about to go extinct, like so many before us. Unless drastic measures are taken. But the only ones who will care are still us, the humans. Maybe we just shouldn't, and die out and let some other, better suited, organism take over. Or none at all. In the end it doesn't actually matter...
Humans are actually special. We are smarter than any other animal on earth and have culture. Human brain is the most complex structure in the known universe, so even on that scale we are pretty special.
And it simply makes no sense to just throw away millions of years of evolution. Your nihilistic worldview is very naive.
To put it bluntly, because the road constant progress and improvement can potentially unveil the meaning of existence of the universe. Nihilism is naive by definition, just because you don't know the meaning, doesn't mean that there is no meaning at all.
