It’s not.
A discussion of the details: https://review.lineageos.org/c/LineageOS/android_frameworks_...
It was a fucking circus. Having a “women only” car at rush hour to deescalate tensions is such a minor peeve in comparison.
It is not the high moral ground solution, and two cars among 20 isn’t a big change either, but that’s the most pragmatic solution to this. Catching some random guy during rush hours when there’s a train every 4 min and thousands of people get in and out is more of a logistical nightmare than how you make it sound like.
Intentional or accidental groping also happens in France for instance, and the best you’ll get will be a passenger fight, no cops nor rail staff coming in to do anything, while the other passengers shout insanities at the fighters because the train is already too fucking late (actually had that once on the train I was riding). The equivalent situation is taken way more seriously in Japan[0].
Patriarchy is strong either way, but I’d be looking at school uniforms more than rush hour arrangements if we want to dig on the topic.