@Crunchyapple sounds kind of like what sensei was saying to the kid who didn't want to wear a tie
Yikes@Windu32
Because girls bear the brunt of sexual assaults in the world (outside of prisons anyway). And we've already seen cases of bad actors dressing up as women to gain access to women-only spaces for nefarious purposes. The point isn't to say all transgender people are pedophiles. Obviously they aren't. But keeping female spaces female will prevent a certain amount of sexual assaults each year. At the very least there should be some kind of threshold to be met to gain admittance beyond simply saying "I'm a woman!" to enter, AND at some point the preferences of the majority of users of said locker rooms etc., should also have a say in who gains admittance. The trade-off for preventing those sexual assaults is transgender people don't get full access showers, locker rooms, etc. Reasonable people can disagree, or find other solutions.
And yes, it's "discriminatory," just like having separate men and women's bathing facilities is already discriminatory. The question is whether it's useful discrimination, whether it's in society's interest. You might as well make the argument that banning men from showering with pre-teen girls in public locker rooms is akin to claiming all men are perverts.
As far as who makes the rules, well for starters, don't you think women should determine who can enter women's spaces? And yes, tying 'womanhood' to birth-giving - ie to having things like a vagina, uterus, ovaries, etc., is absolutely necessary because that what the word woman means: An adult human female.
If you're a man who wants to live life as a woman, great - you do you. Wear your dresses, put on your makeup. But you're still a male living like a female, because we have definitions for how to identify the 'female' of a species (hint: in mammals it has to do with reproductive organs). We know that humans are male and female just like we know that dogs, cats, horses, cows, monkeys, etc., are male or female. And "girl" is the term for a young human female, and "woman" the term for an adult human female.
Wishing you were something different doesn't make it so, and yes, society should absolutely push back on any trend that defies common sense.