You post telling someone to fuck off, it is abuse. We have neither the time nor the inclination to try and divine the meaning behind the post, and whether you are mates with the recipient. RAWK is not a chat room. The offending post was on the main board, so does not even get the slacker treatment of the Boozer.
That said, the warning fell short of the level required to mute you, so there are no material consequences to it. Just think of it as a suspended sentence.