The US stalls aren't exactly see-through: they do not go from floor to ceiling, but only a very tall woman with heels on might be able to look over the walls.

You can look under the door, if you put your head almost to the floor, but women don't do that to other women.

US bathrooms also have cracks between the door and the front walls where the hinges and the lock are, and, while you can't get a perfect view of the inside unless you put your eye to the crack, you can kind of see what the person inside is doing.

I don't think that whoever designed US bathrooms ever came close to imagining that one day men would demand access to women's bathrooms under the guise that biological sex doesn't exist, so the designers probably thought they'd given women enough privacy.

I actually am less frightened in US bathrooms when they are actually sex-segregated than in the group cubicle bathrooms, because a man could push you in the cubicle and assault you with no one knowing, whereas in US bathrooms, other women who entered the main area would be able to see and help you.