Ironically, I agree!
We know the effects of segregation. Turning a two minute bathroom break into a ten minute one because you expect us to search around for the correct negro — err, sorry — trans bathroom is going to add up. It’s going to add up into missed hours at school. It’s going to add up into missed time at work. That’s going to impact our performance in either area which will cascade into further problems with poverty and discrimination.
Your “solution” is in search of a problem. You have no evidence that accommodating trans people in existing facilities will increase any risk to cisgender people. So you have to make shit up like “social mores.” That social more being, “trans people shouldn’t exist.”
That’s the denial you’re in. 17 States with nondiscrimination ordinances for decades. Canada with nondiscrimination ordinances for years. Neither has experienced a macroscopic increase in assaults in bathrooms. There is no evidence to justify this position, so the only reason to maintain it is the belief that trans people should be separate from cis people.
This is a position you have implicitly taken and thus far refused to actually justify because you seem to think social mores cannot and should not be challenged on the basis of their irrationality.
I don’t give a shit if you candy coat your idiocy in civility and dialogue, you’re still saying I should be isolated and subject to all the consequences of spending additional time finding the correct toilet to the satisfaction of nebulous unspecified “social mores.”
Here’s my compromise — we take your exact idea of a per-person ratio and use that to instead mark certain bathrooms as being accommodations for assholes and bigots. Then all the assholes and bigots who are scared of trans people can pee in peace knowing that trans people don’t have to share a washroom with you. Because, frankly, I don’t want to share a bathroom with assholes and bigots, and as long as we’re saying this is a belief that should be coddled to the point of introducing building codes, I think I have a case to say that assholes and bigots should be segregated from the sane and rationals.