> What it needed was for strong left-wing people to stand up and denounce the distraction

Here's the reality: very few people actually believe climate change is an existential problem. As you say, this is abundantly signalled by very few folks being willing to compromise on other beliefs to advance it.

Want to build infrastructure? Cut taxes? Suddenly, people can put their differences aside. Want to do anything on the climate? Everyone has a policy bogeyman to attach, whether it be union requirements and gender issues or immigration and religious tests.