"The government can't grant immunity for that." ... come on.
I don't recall the exact wording of that law, IMHO it already covers such argument, but if not, it just needs a single sentence amendment. Government certainly can grant immunity against pretty much any civil claims.
They also can pass a law stating "Any and all contracts between Apple and 'gareim' shall be considered null and void.", though they probably won't do that - but adding an exception to the laws regulating advertising truthfulness is trivial. In fact, they could simply revoke those laws and then noone could bring any class actions for 'being sold a product on a lie'; class actions as such were only made possible by specific regulations and congress could eliminate the whole concept of class action suits if they wished to.