My Autistic Spectrum kid (17) who is a highly functional Aspergers often uses spectrum-like derogatory terms for his mistakes or uncommon responses. It's not really like he's being serious about it, it's really become a adverb or adjective at this point, same as when he say dork or butthead... he'll say autizmo etc. and I hear him use it often against kids who may have the spectrum deeper than he does or online while gaming. Personally I don't like it, because it's like saying what he has is bad or wrong, which he is neither. But it is the same as when I call myself an asshole so I can't say much about it.... I guess I just wanted y'all to understand where that bully was coming from. He may say "autistic girl" but I don't feel it is meant as viscously as some may think. In case it shocked you, it's not as completely ruthless as it may seem.