Because if you believe the stories, Vince does most things based on what he learns of people, what he's heard recently, and then flies by the seat of his pants. Heyman needs wrestlers to put between himself and Undertaker, who despite being a heel is still over with the crowd. This would logically start with Heyman trying this tactic mid-carders (like Kanyon), who get wrecked by Taker, and then it builds from there. Kanyon decided to mention to the company that he was planning on coming out. Vince is Vince, so his brain puts it together that Kanyon is a faggot now, Kanyon needs to pull his weight to justify his paycheck, and other angles need mid-carder bodies to move forward. If you study "Vince logic" without strictly trying to justify it morally (because a lot of his decisions aren't moral or in good taste), it makes sense.