raise flop and fold to 3b is exactly right. Often in this spot he has an 8 and is trying to protect his hand from you on the turn... so as played I would call.

not raising flop makes the other streets MUCH tougher and we lose value from all the silly 6 hands that call us that we're never paying off when a 9 or 4 hits. If he 3b flop, easy fold. If he flat calls, it's pretty obvious what he has (a 6, but if he goes apeshit later I'd watch out). Bet turn strong again, enough to give him bad odds if he checks turn.