That doesn't address either of the things I said, so I'll restate them:
1. Anything he did was optional, it was therefore not a work assignment.
2. If such a report was solicited (which I don't actually agree with in the way you're implying), the way to provide it wasn't to post it on public company mailing lists, but to give the report to the people in charge of the class.
Do you disagree with either of those claims?
I'll now add a third one:
3. A "report" of the form he provided wasn't solicited by Google. They solicited feedback on the class. Your claiming this wasn't feedback on the class. Therefore it wasn't solicited.
The second one is completely wrong, and I think the first is though I'm not certain.
* No one was looking for feedback on the class as far as I remember.
* He went to an external session to learn how to improve their own processes, which is the report he wrote. I believe in one interview he said his did do it at some manager's suggestion, and so did use work time for the trip with their (figurative) blessing.
* He sent his report only to one or two internal groups, never a public internal mailing list (one was meant to privately poke holes so submitters could improve their arguments before submitting it to HR or whoever. I've heard conflicting stuff on the order of events, so he may or may not have sent it to HR).
* It was the internal quality group that leaked it to a public internal mailing list instead of maintaining privacy.
This is the problem with these things. Literally every claim you've made is wrong. I don't know where you got it, but if you aren't a google employee, I can promise I'm more reliable than whatever you got it from. But nothing I can say is verifiable, except through oft-contradictory leaks. It's infuriating and unproductive, so I'll stop.
1. Anything he did was optional, it was therefore not a work assignment.
2. If such a report was solicited (which I don't actually agree with in the way you're implying), the way to provide it wasn't to post it on public company mailing lists, but to give the report to the people in charge of the class.
Do you disagree with either of those claims?
I'll now add a third one:
3. A "report" of the form he provided wasn't solicited by Google. They solicited feedback on the class. Your claiming this wasn't feedback on the class. Therefore it wasn't solicited.