You can criticize being wrong, but why is the doomer argument "misanthropic" or "malevolent"?

I can answer this, because it assumes that we're too stupid, too greedy, too cruel, to change our behavior and do the "right thing" for people when the chips are down. It assumes the outcome is "doooom!!!" from the start then works backwards to justify it. If things necessarily will turn out terrible, then obviously someone is at fault, no?

Doom is not a logical outcome given the current human condition.