Tbh, I don't see why swearing is disallowed as long as it's not used for flaming. When people say "frak" for example, it's pretty much obvious what they actually want to say.
There, I said it.
Other than that, made up insults (as long as they are not relevant to anything already existing) add to the lulz of an encounter, the way I see it. They are nothing but a source of humor as they are definitely not insulting enough to be taken seriously.
