He was using company resources to respond to a company request for him to provide feedback to a company event.
When the company asks you "tell me what you think about the content of our diversity training, we promise your response is confidential and we are interested in hearing what you have to say", and you respond with an evidence based argument that the diversity training is incorrect, then this is a very different situation from the head of diversity making public comments on a blog. Remember Damore was a non-management developer.
If you are going to fire people for their views, which is what apparently Google has no problem doing, then the Damore situation is much less justifiable than this situation and the person with the offending views was not even fired.
I don't have all the facts, but this article [1] seems to refute your accounting.
The memo was initially sent to Diversity Training, then after a non-response, Damore himself circulated to a wider internal audience.
According to Google [2], he was fired because portions of his memo were found to be a violation of Google's Code of Conduct, specifically "each Googler to do their utmost to create a workplace culture that is free of harassment, intimidation, bias and unlawful discrimination."
But again, this all misses the point--a 2007 blog post when you were not an employee is much different than sending a memo internally while on the clock.
That seems like a pretty shallow distinction considering Google's "bring your whole self to work" policy and cultural norms. People at Google regularly expressed far more controversial opinions than Damore's using company resources on company time. Further, the explicit rationale for canning Damore was not that he was expressing himself on company time or with company resources, but rather the patently false notion that his criticisms of the company constituted a hostile work environment.
Of course he was only fired because he was criticizing popular regressive policies and that provoked the wrath of employees who identify with those kinds of policies, and management decided it was easier to give in to the authoritarians (indeed, Google's management the authoritarian employees in question are probably not distinct groups--they certainly overlapped).
In Damore's case: He was asked to privately(?) provide his thoughts to the company(hence while employed and on company time).
Bobb's case: He decided to write a blog post. No-one asked him nor compelled him to share his thoughts.
My view is that firing people over views and opinions is dumb as long as they are not trying to force their views and opinions on other people in the workplace.
On the other hand, my view is that one's views and opinions are private and don't need to be spewed everywhere, hence why I have a dim view of social media(notes the irony/hypocrisy of posting this on HN).
Bobb's blog post was from 2007.