There is a big difference between going on Facebook to talk shit about your employer and what happened here. The memo writer asked for feedback on his memo and was ignored. He tried again and again to get feedback on his opinion internally until turning to the Google internal 'skeptic' community. The skeptics doesn't quite like what he wrote so they strung him up and made an example of him. He was encouraged to give feedback like this so that the company could react to internal problems and self correct before they became worse. In a collective sense Google is acting like a child by refusing to address this problem and their reaction will alienate employees more than this memo ever could.
On a personal rant, I've contracted for Google doing software architecture on a few projects. They do have practices which mildly disgust me. Stuff like flagging people as 'diverse' and making sure the correct number of diverse people are in attendance.