Maybe one of the hardcore fans here can answer this....
Maybe I'm being a tight-ass and reading too much into this, but I'd still appreciate an answer.
I'm not really a Rocky Horror fan, but I know a number of people who are, and I'm somewhat familiar with the history of the film and its fan community. I understand that the "spirit" of the Rocky Horror fandom is (and always has been) one of acceptance and tolerance, making people comfortable in their own skin -- especially when it comes to sexuality. Why, then, is one of biggest callbacks calling Janet a "slut"?
I get that it's supposed to be a joke, but isn't labeling a woman a "slut" for her sexual practices and preferences...well, slut shaming? If I remember correctly (it's been a while), Janet has sex with two men in the movie: one of them basically rapes her, while the other is a partner her of her choosing; how does that make her a "slut"? How (and why) did that particular callback start, anyway?