You goto see the funny side. Perhaps there is a valid reason? Maybe you were mistaken for someone else who had earlier caused problems on the forums or perhaps someone is personating the forum Administrator to cause trouble.
Was there something wrong with your site you advertised? Maybe it had adult content and caused offence or something?
Did you recieve that reply in an actual thread? If so - can we see the thread itself?
I would say it was an unfair response, if there are no other elements involved.