As we dont have the gaps in my country my guess is it a US interpretation of Jeremy Bentham's panopticon as applied to the shitter.
I expect in the USA people, particularly the out groups, are believed to be inherently criminal/immoral and need to be observed to make sure they aren't doing anything undesirable.
As the US public toilet is primarily a place for moral judgement and not elimation of waste you then get the crazies questioning if people's gender and equipment meets moral standards for use of the facilities based on casual assessment of their appearance.
This is a huge deflection from real issues. Rich cunts got richer, monopolizing our countries abundance of natural wealth and stacking the system in their favour through decades of government lobbying and corruption. Then they pay some fuckwit influencers to push the line that its the immigrant's fault. They have been doing this shit for at least a century and its so fucking obvious if you spend 5 minutes researching shit.
BTW Immigration rates are high, not because of bleeding heart lefties, but because rich people have a pyramid scheme based on population growth pushing up property prices and want us to keep fighting for jobs so we aren't in a position to demand better wages.
Immigration levels are too high because it benefits rich cunts. Join a union or environmental groups and vote on your own self interest and don't be a sucker.