I think everyone is thinking at least 1 level deeper than me.

You have a non-nut f/d on drawy board. Villian over-bets. To me, he is "protecting his hand from draws". Either you should fold (because you are sure he will call any raise, and your implied/pot odds are not there), or raise to get him to fold.

I can see that a non all/in raise may spook a thinking player... but not into folding. Ah! Maybe you get a free card on the turn? Kinda turns your hand face up though.