I think the reason the grope is treated like that is because of how difficult it is to tell the difference between something relatively innocent or accidental vs something meant to be sexual when the act is grabbing someone with your hand.

I don't like it either, but it is like the art vs pornography thing op was talking about. We keep it vague to allow wiggle room for those exceptions. Texas also will let you off the hook for diddling a minor if you can prove A) you didn't know how old they were at the time and B) the judge deems the minor in question to look enough like an adult that you don't look like a dumbass for not questioning it.

Of course, corrupt or power tripping officials exploit that so their (((friends))) get away with things but they can nail your ass to the wall.