I think something that factors into all of this is the common FRPG assumption that gender roles- other that the procreative aspect, of course- within the campaign world has no real difference. Women are able to be whatever men can be, and vice versa.
Yet this is clearly not the case in most major societies forming the underlying model for a typical FRPG.
Yes, I know that PCs are exceptional people...but some of these societal/institutional rules were absolutes.
Consider: a typical FRPG religion has clergy of either sex- yes, there are exceptions, but they're a notable minority- but most RW religions have distinct roles for women and men within the faith heirarchy. Ask any practicing Catholic- there is a HUGE difference between a Priest and a Nun...the latter are the real hard cases (which is why I love my Reaper Battle Nun minis).
In some societies, a woman bearing arms was arrestable on sight. In others, unmarried women couldn't appear in public without a male relative.
The Amazons of legend weren't the norm, they were the extremely exotic exception.
In Earthsea, scholarly magic (such as on Roke Island) was limited to men only. Witches, the exception, had no real organization to foster their training.
So, again, the ban potentially robs good players of the opportunity to play good characters.
Banning certain people from playing cross-gender PCs, OTOH, I can understand, but still wouldn't support. Nobody should be playing a PC that someone finds deeply offensive, but rather than ban a PC concept, I'd favor a sanction on the player, like kicking them out of the group for a while.
Because, doggone it, I'm a Catholic black guy who (besides playing the occasional female) might one day might want to play a Chinese Buddhist or "Deep South" member of the KKK (again). If I don't support my fellow gamers' desires to play unusual/oddball/ PCs that are in some way against type, they won't support my desires to do likewise.