actually a workplace should be your workplace, not your political debate site.
yes free speech is important. yes it's bad if people discriminate. but did he had other choices than just raising the topic again, in a "google" public forum? yes he could! but he did not, he could've mailed his HR guys or talked with his manager. or both.
but raising the same topic again and again and the same disucssion occurs with no end in sight, is always a bad idea (regardless of the topic).
p.s. i go to work because i love programming and not because i can raise political discusissons over and over again with my co-workers.
Since the external links are private, it's hard to know if we're comparing apples to oranges; but it's informative to contrast the reaction to Damore's single memo with this fellow's repeated, willful flouting of his superiors' requests to moderate his tone and stop posting long enough for the topic to calm down. It seems like they gave Cory a lot of second chances and leeway.
I think it's appropriate to ignore whether a co-worker thinks the moon landing was faked, or what sports team they like, or if those idiots they heard about in the news are a big deal or no deal at all. That's simply not what the workplace is for. To the extent those discussions happen, I view it as a partially-voluntary leaking of their personal lives. Nothing to condemn or engage in, just politely ignore it until your lunch finishes in the microwave. The idea that people would want to express any views in some type of organized way inside their employer's organization makes little sense to me -- I find it unprofessional but not outrageous or anything.
I think it's clear whether something is an on-topic professional comment. All discussion of news stories is a 'no' unless it is e.g. a new regulation on the industry or their customers that was just announced.