Well, just try obtaining some of the Negro League HOFer postcards, and you might get a different perspective on just "how much love" PC's can get!
Of course, that has to do with them sometimes being the only option available for those players. But I personally think postcards are TOTALLY legitimate "cards" and am often willing to spend as much as I would for a trade card, if the card meets my other criteria. But you're right about the disrespect felt by many collectors - provides good bargains sometimes!