Heh, the terms gilbuyer and RMT lose their credibility over their excessive use over the years. People say these things freely and openly on a regular basis and thus the grounds/merit for many accusations made for someone being associated with RMT activities are nil.
Hell, why call someone an *** when they're rude or disagree with you? Just accuse them of buying gil or being RMT. It's equally insulting and has just as much grounds of being true or false.