Think about it. From the author's other works, we've had Briony, who was a case of Break the Haughty, and Missy, who was sort of a Take That, Scrappy!. But he's never had a Break the Cutie type Sanity Slippage. Being the one who tries to be positive, all the scheming and drama could push her over the edge.
Oh come on. Stanley is the only gay member of the cast and Dirk is as Camp Straight as they come. Stanley will definitely mistake him for another gay guy like everyone else, except that it would mean more to him than the others. At the very least, there will be some remark along the lines of "Well flamers aren't usually my type, but it's still nice not to be the only gay guy any more."