It’s always amusing to me to see this kind of argument. There’s plenty of things that are not illegal, like sexually harassing/nagging a woman verbally (without threats) for example, but is obviously ethically and socially problematic. I’m going to assume you already know that so either you mostly believe what OP is saying and know what this guy is doing is dubious at best or you find OP to be an unreliable narrator and is playing it up for points. Based on your other comment, it seems you’re just here to play the contrarian.

Probably indecent exposure arguably, sexual harassment if he doesn't stop when asked to? IANAL ofc, also mindset might be a requirement for some of the laws