The content of the game is irrelevant as far as the content allowed on the server, for the most part. No matter if the game is insurgents vs. marines, racism WILL NOT BE TOLERATED, particularly from clan members. If I see a clan member making racist comments, rest assured the ban hammer will fall, and quickly.
Now, that said, there are some grey areas, as Herm pointed out before. You all should know what is appropriate and what isn't. If it is something you wouldn't say in front of an audience of 32 strangers in reality, what would make it appropriate to say on the internet to an audience of 32 strangers? You don't know who is listening, and what their background is, or response will be. So your best bet is that if something seems iffy or possibly offensive, JUST DON'T SAY IT. Remember, when you have our clan tag on, you represent us, and we hold you to a very high standard.
The point of these rules isn't to censor your speech, or to give admins something to do. The point is that by holding and enforcing these rules, we foster a better environment for gamers. Things like the occasional curse word may not seem like a big deal, and to tell you the truth, it's not. However, go to some of the un-moderated servers. Things are often so chaotic, or downright abusive, that it's not even fun to play. I don't like being repeatedly cursed at or called a "Noob" because I'm not the best at the game, so I assume the others don't like that treatment either. This is why we have these rules, and why we actively enforce them.
It's about respect. It's about good sportsmanlike conduct. It's about having the most fun, best servers around. Racism is counter to all of those things, and will not be tolerated.