I hope these don't get downvoted due to merely being humorous, but having taken Andrew Ng's online Stanford class in ML, the takeaway for me was indeed "this is just linear algebra at a massive scale" (fortunately, I enjoy linear algebra!)
To my mind Google had only two choices. They could either fire the guy or use the viral memo as an opportunity to be a thought-leader. There was no way for them to pretend it didn't happen and no other 'quiet' way of handling it. They should have challenged the content of the memo while applauding the courage it took to write it. They had, in the author, an employee willing to think critically about something they say they give a damn about and someone with demonstrated capability to generate discussion. Why not leverage that opportunity to work towards making the (tech) world a better place for everyone?
https://www.xkcd.com/917/