I am not because I live in a pretty conservative area. So I try to get some leftist points through to coworkers without opening myself up to the ridicule of just being a “commy degenerate” in their eyes. So I think I can get through to them better without outting myself as a Marxist.
I don't go around saying "hi I'm a communist" but I have a red star on my hard hat, and when politics inevitably comes up, I don't pull any punches. Had it gotten me in trouble? Sure. But I have moved a lot of lib/chud coworkers positions