Public restrooms are a sign of advanced civilizations. It's a pity that they have to be built to withstand damage from hooligans.

The restroom building provides more utility than most buildings do to a hooligan. Unclear why it is an enemy.

Vandalism scales linearly with [accessible, visible, unsupervised].

Uncorrelated with the usefulness of the building after controlling for other factors

Any "private" space in a public place becomes valuable with more density. It's basic scarcity incentives. It unfortunately incentivizes hooligans to make the restroom appear even more disheveled and unsafe to increase the privacy (less people want to go in it)

You're reading way too far into it. Private spaces are simply easier targets.