Why would corporate right wing neoliberal democrats scare the bejeesus out of their petro-donors by making climate change a hot topic. They know damn well that 99% of their base will vote for them no matter what they support, just to stop Trump if nothing else, but not to stop the republicans / democrats / Trump’s agenda. Why do you think they are hyping this Russiagate / Mueller conspiracy theory. In this way it serves the demorats interest to have more and more extreme fanatics in the republican lineup. Sometimes they win, sometimes the republicans, but always the neoliberals and never progressives. The public will has absolutely no effect on legislation in this country, only money plays a role. What democrats are afraid of and desperately trying to prevent is left wing candidates like Sanders from winning the day - they would rather have Trump than him.
look at this video: