I don't think they're lazy cowards - or rather, I think "lazy cowards" is something lazy cowards say to explain away lazy cowards they disagree with - I think they grow up in an environment where admitting fault or even suspending judgment is something that will get you attacked or taken advantage of. Whether by parents, teachers, classmates, friends, politicians, cops, priests, or gods.

Children aren't great at lying. If they don't believe they are a good person, people will notice that self-doubt and take advantage. Believing you are axiomatically good is safer, protecting you from bullies of all kinds who are looking for someone who won't resist being punished.

Properly dealing with climate change often requires a major lifestyle change that is largely outside of people's control. It's natural that people who haven't processed their childhood schemas would respond to it according to those schemas, and that for people whose childhood schemas are centered around avoiding responsibility they respond by stall tactics like pretending climate change isn't real so people waste time proving it to them.