reality isn't doomerism, really just is.... reality. Those who call it doomerism live near a river called denial, apparently it's a pretty popular place these days.
They either don't want to think about it, or they think a man is going to descend from the heavens and save them, I wouldn't count on that happening.
There's room for hope we can science our way out or at least ai might be able to find solutions we can't think of, assuming it doesn't kill us first.