I wonder if the “not dressed like that” isn’t so much a testament to how the Sheriff thinks gay guys dress, but to how he knows Stiles acts when he is trying to impress someone he likes.
Because Stiles did dress to impress for the prom when he was going with Lydia. And he seems to the type, as shown in other ways, to go ALL OUT when he is interested in someone and thinks he maybe possibly have a shot.
“Not dressed like that. I remember when you first met Lydia Martin and you wore a suit to school every day for a month, even though you were in the second grade and had no earthly reason to wear a suit. I remember when you met Deputy Smith’s daughter and dressed like you worked at Hollister for almost a year until you realized that her “best friend, Mary” was actually her girlfriend. I even remember when you first met Scott and wanted him to like you and convinced your mother to buy you a copy of whatever t-shirt Scott would wear so that you could have a copy and you could wear them and be twins because Scott didn’t have anyone else to wear Wonder Woman t-shirts with. YOU ARE NOT SMOOTH STILES AND YOU WOULD NEVER WEAR YOUR SOMETIMES PJ TOP TO A CLUB IF YOU THOUGHT A PERSON YOU LIKED WOULD SEE YOU”
(Source: belastalbot, via thevoiceofwrath)