WoW has changed considerably over the years, often for the better and sometimes for the worse. Better and worse are, of course, a matter of perspective. Slovotsky of Turalyon is getting fed up with people complaining about the easing of raids. He's confident that Blizzard made the choice to lower the difficulty on raids because more of the player base can now have a chance to experience them. He disagrees that casual players have ruined the game. Familiarity may also lead to boredom. Some of the guilds that have progressed through Naxx have already done so either in the Pre-BC era or on the PTR.
As some pointed out, Blizzard is a for-profit business. The company's job is to sell a product, not to rule with a heavy hand or coddle the incompetent. The switch to an inclusive raiding environment was most likely a marketing decision. Caydence of Draka drove this point home, to rebut the argument that players will quit WoW because it's easier. It is simply a better business decision for Blizzard to alienate the "hardcore" players who make up a small minority. She suggested that the subscriber base has grown with each ease in difficulty.