I can’t speak for specific rules about slurs - I strongly suspect that it would be a case by case basis, and highly context sensitive. I very much doubt that they would be used in a CoG game. But I can offer my opinion.
Including real-world prejudice is a decision that shouldn’t be made lightly, and it’s worth considering what effect you’re trying to create with it… and what unintentional effect it may have, whether to a player who may be thrown out of enjoying the game, or making unintended implications about your setting.
Sure, misogynistic slurs show a misogynistic setting. But they harm real people in the real world, and can alienate a female player and make it feel like a game wasn’t written with them in mind (yes, not every female player will feel this. No, this isn’t a reason not to consider it very carefully). Does the setting need to be misogynistic? What does that achieve? Does calling a sex worker character a slur achieve anything other than making the character, or player, feel small? Is there another way that a villain character can be shown to be a jerk?
Fantasy and scifi discrimination has its own issues. But it has the advantage of not using words and concepts that directly harm people in the real world. Weyrwood handled this well, weaving class commentary and fantasy prejudice together in a setting that strongly evokes Regency social mores - without using real-world-harmful language. Isabella Shaw’s interview is recommended related reading.
Finally, this topic seems related to the question of how to handle discrimination in games, so if you haven’t read the following topics I’d recommend having a look: