I follow the discussion about CoD2 loosely.
Is the release of patches and modding tools the duty of the publisher?
Actually I only buy the game.
So I see this as voluntary or additional output.
But I wouldn’t be a fan of publishers that don’t release patches and tools.
I think those releases show that the publisher takes care of the fans / fanbase.
It’s their duty to support games for a reasonable length of time with patches unless they release a bug free game. 
It’s not their “duty” to release modding/mapping tools, but it’s probably good for business in the long run because it gives games a longer shelf life and makes it more likely customers will buy sequels (which usually are several years apart). Counterstrike is of course the ultimate example.