Ok so the reason that has been stated for why microsoft are doing this is because if they let it be released for free, it would make similar content appear poorer value, and would create demand for cheaper or free content of simialy quality on XBL. Thus Microsoft are trying to artificially inflate the perceived value of their DLC in order to keep prices high. and they're doing it with other people's content.
Also the fact that it is such an odd number at 560 MSP, and from what valve have said leads me to conclude that Microshaft's cut from an 800 MSP DLC is 560 fricckin points. THAT is reprehensible!
And to some people $7 is a lot of money, I remember when I was a young'un I would get like maybe 1 game for my birthday, maybe another for xmas, and even if it isn't much money to you, the difference between $0 and $7 is still infinity percent. that's a lot.
Oh and I don't think some of you understand the reality of server costs, XBL is a cash cow for microsoft, they make a huge profit on your subscriptions, way over what it costs to maintain the servers, and they post massive videos and demos that are all free to download, hell the demos are almost always the full content but locked. they do that because to cost of serving the file to you is miniscule vs how much they make from the license the charge on the 3rd party games, that a few people might buy after trying the demo. the cost to serve you this DLC is maybe a fraction of a cent. so don't be defending that. the fact that they charge a monthly sub, just means that it should cost less, vs a system such as PSN or the PC where there is no paid for centralized system.
The solution here is simple, Valve should offer free PC game keys to anyone who trades in their 360 copy. That way they obey microsoft, but give loyal fans a way to protest this pathetic move by microsoft without having to boycott the new content.