First of all, any re-raise here at least 3x his bet amount is going to commit hero to this hand and if the guy pushes over top he has to fold with half his stack in the middle. Also this play doesn't extract chips from worst hands, in this case the only thing that is going to call you is flush/maybe 2 pair and let bluffs/TPGK get away from his hand. Second of all he is not drawing to the nut flush, he is drawing to the second nuts and could already be drawing dead if villan holds the As. The way he played it is a better line then what you are saying because atleast he had the chance to extract more chips out of worse hands.