That probably applies to 共匪, but 五毛党 (50 Cent Party) or 五毛 (50 Cent) are reasonable terms that can be used to discuss a particular phenomenon and don't carry anything inherently insulting, the only insulting part is the reference to that group (so if someone considers that group to be immoral, then associating with an immoral group may be considered as an insult) - if everyone decided to call them "fluffykittens" then soon "fluffykittens" would be a trolling term and insult in some sense, but that definitely would not be a reason to delete posts using "fluffykittens". Clear nominative use should always be allowed. I mean, calling someone a troll is an insult pretty much equivalent to 五毛党 but we clearly want to be able to talk about trolls and trolling here, and we want to be able to call someone a troll even if that might insult them.
To invoke Godwin's law, calling someone a nazi is usually an insult, that does not justify deleting posts using the word "nazi" even when clearly using to associate someone's actions or behavior with nazis - a reasonable discourse needs the ability to equivocate bad actions with other bad actions, comparing them with appropriate labels, and there are actions where every appropriate label will be insulting simply because the actions themselves are bad, and every non-insulting label will be unappropriate whitewashing.
To invoke Godwin's law, calling someone a nazi is usually an insult, that does not justify deleting posts using the word "nazi" even when clearly using to associate someone's actions or behavior with nazis - a reasonable discourse needs the ability to equivocate bad actions with other bad actions, comparing them with appropriate labels, and there are actions where every appropriate label will be insulting simply because the actions themselves are bad, and every non-insulting label will be unappropriate whitewashing.