Christianity, like every single other human cultural institution, hasn't exactly covered itself with glory about how it treats women (and, therefore, the temptations to damaging behavior it inflicts on men).
It is common for religious institutions to ask guests to have "respectable" or "modest" dress - guests of both genders. The definition of that is usually something like "don't show a lot of skin." However, there seems to be always a tendency for more than 50% of the concern to devolve on women.
At a convent in Meteora - yes, a convent - for women religious - we encountered the demand that the female members of our class wear skirts. This was the done even though all of them were dressing "respectfully" by most any criteria.
Within Islam the moderately conservative position is for women not to show the shape of the body - thus presumably banning yoga pants. Apparently some Christian schools in the U.S. also follow suit in that regard.
Men who came to this convent in shorts or with no shirt would also be told to cover up - but still, this particular practice for my female students seems particularly irrational.
Thanks to all of them for treating this as a lark and viewing the issue as one of being a guest in someone's house.