Surprisingly many people in the linked Reddit thread seem to think that open source license means Google can re-license the code and strip the author info.
We are beyond this now, if you complain, they can have an agent rewrite it and then it's not copied anymore. It doesn't matter and the bigger wallet wins, let it go.
Which is the one thing you absolutely cannot do.
if there was a comment that said // TODO(username) and google removed all comments, is that violating any license?
It seems like an open and shut case, and I hear this Google company might have a few $$$ to pay for a settlement ...