Xzi said:
No, that's not a good reason. Not for day-one DLC, anyway. For any other DLC, yes, I understand it's extra content. But if they're charging you for day-one DLC, that's stuff they could have easily included in the original game, or at least given you for free because they failed to fit put it in. Charging for day-one DLC is pure gouging of the consumer; very greedy.
Your first point is rather off; in order the include it in the base game, they'd have to delay getting ready for the release for a few months, which would push the release date back, and so forth.
As for whether or not it should be free is a matter of opinion. I don't see any reason why they should have to give away anything for free, especially considering that it isn't part of the base game.
Sure, it'd be nice if it was free, but just because something would be nicer doesn't mean it's the way it should be.