Ultimately, it speaks to people's lifestyle choices. In the US people are used to a particular standard of living: driving big cars and eating big steaks. If you tell people you can't have those things, they will have a visceral reaction. Politicians caught wind of this and turned it into a divisive left vs right debate. Im oversimplifying, but at the core its an incentives problem: Why should I tighten my belt today for some future payoff I may not even be around to see?
It's more like - why should I tighten my belt today when the celebrities, politicians and corporations making a big fuss about climate change are still flying around in private jets, buying up coastal property, eating steaks and are responsible for the vast majority of greenhouse gas emissions?
What kind of argument even is that? What's next - "why should I care about hurting you when there's so many sociopaths out there that clearly don't"?
The people spreading fear about environmental collapse and claiming to be terrified of it, are displaying behaviors that contradict their claims. The people saying the ocean is rising and going to swallow communities while buying mansions on the coast and flying around in private jets, are either displaying extreme cognitive dissonance or aren't really that concerned with the environment collapsing. If it were one or two individuals displaying this behavior I'd blame cognitive dissonance, but it's pretty much every high-profile politician / celebrity.