Yes no-one reads the ToS but by the same token we all know we take a risk when doing so. Google did nothing wrong in this instance, they just held the person to an entirely reasonable and fair condition of use.
That's like a criminal blaming a witness for them getting caught.
If the lie wasn't there nothing would have happened, you have to look at the root event, not what followed.
That inability to form contracts below a certain age actually protects children and is in their benefit, no-one should want it removed. Yes there are situations where it seems overkill but on balance it's a good thing.
So given that the law is reasonable it has not, as with most things with kids, fall back on the parents.
(Note: My understanding of the law is based on English law rather the US law but I'm guessing that something similar applies)