@Thulpelly
What do you think their ‘other motivations’ might be?
I think for some people, being a righteous warrior against the world is psychologically seductive. The more people oppose them, the more their virtue shines, in their own self-image. Making their view the boring consensus, by winning hearts and minds, would actually remove that.
You see something similar in the 'sheeple' rhetoric from conspiracy theorists. Others are just too stupid, or too selfish, to care. Not like me.
That partly explains I think why some people seem to switch from far-left to far-right and back. What they really want to be is a radical with a simple answer.
I'm only talking about a small fraction of environmentalists, of course, but it's a very visible bit. And odd that more mainstream environmentalists don't seem to disavow them, which would win some goodwill from the public I think.