While Activision are correct seems to me they're finding it's not going to be easy to try and have an exclusive deal on one console while trying themselves to offer a cross-console elite service offering as well.
Really I don't think the two are that compatible from a marketing perspective and Activision are going to face this so long as DLC hits 360 first. People are going to take Elite and expect that means they get priority - they're wrong, but to be fair Activision is trying to mix two messages here and this won't go away as a result.
Try to be reasonable... its easier than you think...