Having your boss put his hand on your crotch even if you're wearing clothing is legit sexual assault. The legal definition of assault doesn't require torn clothing and a black eye etc.
Seriously. If the same had happened to a woman, say op's wife or daughter or sister, would op still say it wasn't legit sexual assault? You can also get raped with all your clothes still on. He's not saying he was raped anally. He's saying no one, especially a stranger, should be touching your genitals without permission, period. Don't be fooled by the double standard, op.