All-you-can-eat is not the same as unlimited.

So should cloud providers offer all-you-can-store in the future because by your logic that's not the same as unlimited?

An all-you-can eat might ban you for getting more food but they won't pump your stomach to undo all the food they already gave you. Google already let him store that data, if they regret that they should ban him from storing more. Deleting his data after permitting him to store it is completely over the line. No buffet in the world runs like that, not even those owned by literal gangsters.