If the admin doesn't want you swearing on his server, he has the right to enforce that.
Just because you're allowed to/are comfortable with swearing, doesn't mean other people want to hear it at all.
If you saw the person above who swore, being mentioned that he'd be banned if he hadn't left, you'd have known that the admin didn't like swearing at all.
So, you don't go and do something, or even imitate something that the Admin doesn't want to see.
As far as I'm concerned, OSHIZ is the same as Ostuff, and the Admin doesn't want it there, and is allowed to ban you from his server if you say so, especially after the verbal warning prior to that.