[hangphyr]

Another one: "I hate onions". Now, replace onions with a derogatory name for another group. We can't prohibit negative words on account they can be used to express negative opinions about other groups of humans.

In the case of communist bandits, it's a criticism of a political ideology, and in particular here one party. Criticism of political parties and ideologies is completely fine, even when expressing insults to them. Expressing threats of violence or other crimes isn't permitted or moral, but expressing dislike or disrespect is perfectly valid. Can anyone say they've never expressed disrespect to any ideology or political party in their life?

[trasz]

No, "communist bandits" obviously refers to a group of people, not ideology. Furthermore, while you could argue it's about some particular organisation, it's often being used to refer to chinese citizens in general.