OP is really awkward and he could have just cleared it up by saying literally anything. Instead he made it weirder by not talking and playing cat and mouse with someone stalking him. Then he tried acting tough for some reason even though he judged earlier that the man wasn’t a threat to him. If the person wasn’t a threat to you but you still felt they were stalking you, why wouldn’t you just ask them what they’re doing? Instead of playing a passive game of “who’s going to make the move” with a stalker, which, if this guy was actually trying to rob OP, would have ended in a robbery no matter how tough OP thinks he is.

But It’s shitty that this guy tried grabbing his crotch because that’s sexual assault and it’s rough that being a weirdo can get you sexually assaulted. That’s inexcusable regardless of OP’s behavior.