It's not the message. It's the messengers.
There's no kindly way to say this, but I'll do my best. We all want to save the planet. I have plans for my little patch of it. I'd like to have visitors. I'd like their patches to be pleasant, if possible, or survivable for the time it takes to make them pleasant. I'm happy to help, even if it means Democrats will benefit too. But there's not a thing anyone can do when the Democratic Party consists entirely of miserable corporate hacks.
Perhaps a personal story will help. One day I found I had a number of dreadful character flaws. I'll spare everyone the disgusting details and the source of the epiphany. There's a decent limit to confessionals. I realized that I was the problem. To make this story suitably brief, I stopped doing unspeakable things. Everyone said, "hooray!" And we've lived caustically ever after, with moments of happiness.