Because people care more about appearances than reality.
Generally being a commie or a lefty comes together with an image, a belonging to a group. It's not by chance that most commies and lefties look exactly the same and are the same people getting weird hair colors or being degenerates in general that fuck anything and everything. Looking in general for another human acceptance.
Leftism is "politics that sound good", is avoiding personal responsibility for your actions by saying "I'm a good person because everyone should have everything" but without thinking of the consequences or actually wanting to work for this reality and simply giving a check away through taxes as if that would solve anything.
It's the prime example of how destructive good intentions are. It's like the child that gets everything from his parents with no effort simply because the parents didn't want to deal with the kid crying. So you think you can get anything and everything crying, instead of simply accepting the injustice and real nature of the world and fucking working your ass off.