I think its a little less clear for ISPs where large amounts of data usage is normal for average users but in the case of storage, people dumping petabytes of data they don't even care about is clearly misuse. If the drink place stepped in to stop you after 5 drinks that would probably be false advertising.
Yes maybe Google was wrong about calling it unlimited and now they are fixing that by making it not unlimited. That doesn't change the fact that people were actually misusing it