You all miss the point. mkay, as in the South Park satire, was used by a smug, patronising teacher who says it after a lesson in a tone of fake understanding and empathy with his listeners. Nobody would use it as a substitute for 'okay' except tongue-in-cheek, mkay?
When someone uses the term, "Perty Gay Like That, Mkay?", s/he is not in any way referring to a homosexualperson. S/he is innocently pointing out that the person is acting perty gay. This is often confused with actually slandering someone for being gay.