Throw that on the pile of "See what I mean?"
Being in the left means constantly fighting and being attacked by other leftists for being the wrong kind of leftist.
Yes, I've noticed the complete lack of civility, and thus a complete lack of teamwork, and thus an utter inability to accomplish goals. "The Left" doesn't get shit done, so what's the point of tolerating the infighting?
You come talk to me when you've figured out how to get along, work as a team, and are willing to court centrists into supporting you. And not a minute before. If you survive whatever's next.