If you focus on the fact that Google fraudulently marketed an operating system that allows users to run any software they like (until they successfully drove other open options out of the marketplace) you have all the legal justification you need to force Google to back down.
In the US, there's no requirement for a company to honor the claims of prior advertisements for things that they might do in the future for a different product. And even if a company does lie about the features of their product, advertising law does not require a company to change the features of their product to meet those claims. What could be required is a change in the advertising, or a refund for people who bought the devices under the false terms.
But if you advertise a certain side of feature features in a phone three years ago, and sell something completely different next year, that's entirely legal.