To give a different take on this, TJ Cloutier hates playing aggressive vs. raggy flops with AK. I think he's used to playing against people who are less likely to call pre-flop raises with non-pocket pair hands. Against looser competition, it's more likely that a raggy flop means that they have nothing and betting when checked to is more appropriate.

As Fnord once said: "AK isn't a drawing hand if nobody has made a pair. They are all drawing against you!"