I haven't stood in the cowshed this season, as I've transferred to the Clayton End to see how it goes, but I've heard the same people 'heckling' the players. Although I agree that this can undermine a player's confidence, I don't think that any of it was really that bad.
As for Whalley leaving, then I'm sure there's more to that than most people assume they know.
Whilst I don't agree with mindless criticism during the game, as Shaker says, players have got to be tougher than that.