I really don't see the problem here, and I think that the outcries from the community are really just kneejerk reactions against Activision with little bearing on what is being said.
If the existing multiplayer of the game continues to exist as it is absolutely free, but Activision chooses to add something on top of that - whatever it might be - for, I don't know, $3 a month? Seriously, we have a problem with a company offering a premium service for more?
Isn't that, uh... just logical? You pay more for more stuff. Or should we expect all of our advancements for free?