I'm pretty sure everyone knows that. Which makes one wonder why anyone would take the time to vocally complain about an optional feature that they already knew was only around for this game.
Because it doesn't matter if it's something that's around for a lifetime, a single game, or even a minute. If it exists in a product we buy, we are allowed to have some kind of problem with it.
Although I do think if not for the community at large this thread could have been locked right away as either of the wikis or Google would have answered the OP's question.