I actually see this as activision slyly trying to prove a POINT about the expensiveness of consoles (specifically the PS3).
Sony refuses to lower it's cost, in large because (and they have been QUOTED saying as much) people will ultimately pay what they ask in order to own their console which they feel is a superior product to it's competitors.
Activision is simply following that model. If you can hike up a price based on production costs and claim that poor economical conditions are hurting sales CAUSING the rise in price, which essentially Sony has stated time and time again (and to which in many cases I'm inclined to agree) then I do not see any reason why Activision cannot do this to improve profits. After all, the goal of a business is to make a profit, not give away free entertainment to fanboys. Sure, on the consumer end of things it sounds like a dick-move, but in the business world it makes PERFECT sense, and moreso if they still sell a number of copies. They understand that there are still plenty of people who will gripe and moan all the while forking over the money anyway because their desire to own a product supercedes their desire to save money.
So in essence, I make the same statement as I do to people who complain about Sony not giving the PS3 a price cut. You, the consumer, have only ONE power and ability... you can 'vote' with your FEET.. essentially if you think something is worth buying, then buy it. If not, YOU DONT HAVE TO HAVE IT. There is no requirement or need in life to play Modern Warfare 2 or any video game for that matter if you do not agree with the price point. They don't make games for YOU, they make games for a PAYING CUSTOMER. Either save your money and buy the game because you really want it, or don't. Ferrari makes cars that are totally awesome, and I'm sure almost all of us would LOVE to own one, but they price them at what they feel the car is worth and no one complains because we recognize it as a Luxury item and find cheaper alternatives to our vehicular needs. The same applies to games, consoles, health care, and anything else. YOU have to decide if it's worth the price. Free market capitalism regulates itself in this manner, and thats the beauty of it. If the price is too high, consumers wont buy, which in turn causes price REDUCTIONS .. OR... the benefit of a COMPETITOR. The Wii and the 360 are direct examples of this, benefiting from the PS3's refusal to lower the price to consumer demand and causing people to buy a cheaper console as an alternative. If Modern Warfare 2 is too expensive, then another shooter that might be a decent title but was threatened to be swamped into obscurity by the superiority of the modern warfare brand will suddenly be thrust into the limelight offering up a new IP and developer to bring newer and exciting gaming experiences.
And of course there is always Battlefield 3 out there, although that too is owned by Activision.
In short, complaining about prices accomplishes nothing except to make you look like a cheap ass. Activision is only doing what businesses do, just like every other business. This is the reality. Either buy the game or don't, and by NOT purchasing it, you send a message that you and other consumers like you are unwilling to pay that amount for what amounts to cheap entertainment. Nobody stopped going to the theatres when they hiked the prices on everything from tickets to concessions and as a result a date to the cinema is easily worth a day's wages.
Fight with your wallets not your words.