You'll see it in movies, you might see it nowadays more as a joke; when someone is calling somebody a commie it could be because they're trying to insult that person or paint that person as someone who is somehow extreme.

你会在电影中， 在可能更多地作为一种玩笑；当有称某为“commie” 时，可能是因为他们试图侮辱那， 把那描绘成某种极端的。

The question is about the expression " to be a commie" (commie).

问题是关于表达“to be a commie”（commie）。