I hate that mentality. It does a disservice to both Halladay and the league to imply that his dominance in any way has something to do with the NL being "bad" or even "worse" than the AL. It's not like Halladay never put up comparable numbers in the AL.
he noted the fact that Halladay put up astounding numbers pitching in the AL East, but I think his point was that it's a lot easier to pitch against the NL East.