Training a CNN using pictures of faces just got patented

No it hasn't. It's a pending patent application in the process of being examined by the U.S. Patent and Trademark Office.

Google Patents link: https://patents.google.com/patent/US20160140436A1/en

That's it, I quit.

Maybe you could build a book reader that simplifies text or alters the wording of ads based on the eye movements and facial expressions of the user instead :D

This appears to be a pending patent, meaning it will not necessarily be granted. It shouldn't be, because the application describes only bog-standard machine learning techniques with no advances on the state of the art as it was when it was filed.

So I guess all babies will infringe on this as they train their neural networks

Claim 1 is as broad as a barn. They'll bounce it.

Surely.

Won't they?

My understanding of patents (having made a few): as long as you have strong lawyers (and good copy writers), you can almost patent anything. I was shocked by what we could get through.

Well, you can possibly patent anything as long as you respect articles of the Patent Law, but if your claims are super narrow, it is worth nothing, as it would be easy to design around and not infringe.