I'm all for keeping politics out of the workplace, except for verbal conversations between colleagues. But that's just not the case right now.
Both are obviously incredibly unprofessional, but only one would probably face life-changing punishment in reality. Ideally you set the tone that both are unacceptable, that the only political discussion acceptable beyond interpersonal conversation is the politics of the company's self-interest. Both starting an internal political battle, as as well tweeting externally about an already-started one, should get you fired. But that's only fair if you set that tone and expectation.
That's ludicrous. You don't do things that make potentially thousands of your coworkers uncomfortable internally just because you want to make a point. Human Resources is a thing for a reason.
Put it on medium and be done with it.
He suggests that Google has a culture of sharing pretty openly and of offering criticism and even commentary on important issues. It would be good to have additional evidence of this to evaluate whether his statement was indeed matched to the appropriate environment.
(I am not and have not been a Google employee, so IDK for sure. I know that at my company, there are indeed particular fora in which this sort of thing could be raised. I can imagine at some companies this would not be possible, so you raise a great question. Thanks!)
Maybe you are unfamiliar with Google's culture. Employees are encouraged to engage in conversations about the culture and values of the company, using mediums like this. Google is not rigid about "work time", preferring that you are productive.