He definitely took that into consideration, and it fits him perfectly actually.
"Stefon first began as a punk rock
musician. In high school, Stefon and his friends played punk shows in a band called "Om" in which he came to be referred to as "Pissed Off Stef," or "P.O.S." Since then, the abbreviation has been given other meanings including "Product of Society," "Patrick O'Sullivan," "Promise of Stress," "Promise of Skill," "Point of Sale," "Plain Ole Stef," and "Piece of Shit." Stefon has said that "(it) means anything that fits into my song."
I like the anti- "conformist" edge his name has to it, and that's probably the point. People get annoyed by Fucked Up's name too, but it works well for them. Have no idea what people want from these names (they speak way louder than tons of other names I come across).