It's not enforced in the spam boards, and probably rarely will be. That's where 90% of it occurs anyway. It is still a rule for sure, never abolished and only the censor was removed. In this case the violation was too blatant and direct to ignore, and within a board that is part of the game discussion. Whether other mods have enforced it in the past doesn't change that the rules exist and should be followed by everyone. I can't speak for other mods but I can assure that I at least am aware of and willing to enforce the rules as written, within reason. Had the profanity seemed directly offensive to someone in particular (as an attack) it would have been a ban instead.
Swear words can be ignored when they slip by, which is most of what i've ever seen from you. It's different when you use it in an offensive manner like you did there. Obviously you didn't mean offense nor was it aimed at anyone, that's why it's only a warning. A sort of reminder that the rules are the rules and enforcing mods do exist.