But isn't saying "You're not dressed in line with our code for dress and appearance" the complaint here? I thought that with respect to low-cut/suggestive tops, the problem was never that they weren't professional clothing (with respect to the workplace in question) - which of course is an entirely independent and asexual issue - but that some people made inappropriate comments and thought it acceptable.
I think that a dress low-cut enough to be considered unprofessional is a sexual issue by default. Professional standards and decorum exist, in part, to prevent a sexualized environment.
How is it judged that a man's pants are too tight to be professional, or a woman's dress is too short, and what are the reasons? The reasons are sexual, and I might be wrong in this, but I would guess the line exists where people of either gender would begin commenting.