@Bryan10 I'm a single female who hosts a private room in my home. I accept any and all genders and although I get more single female guests than males, all of my male guests have been total gentlemen.
But there have been numerous posts over time on this forum by female home-share hosts who have had male guests touch them inappropriately, try to grab them and kiss them, or continually hit on them even when given unambiguous responses as to this not being appreciated.
And many women have been sexually assaulted at some point in their lives, and wouldn't feel comfortable being alone in the house with a male who is a stranger to them.
I don't think it's fair to judge women for having a "females only" designation when they share their home. You aren't a woman and obviously have no idea why a female wouldn't feel comfortable with a male guest. It's not about asssuming that all men are bad and dangerous.
And it is within Airbnbs TOS to state one gender only when home-sharing. You could state "males only" if you wished.