In my history of corporations, almost all bad behavior goes unreported because those in power are doing the bad thing. It seems like Google is not different in this respect.
For group discussions with no negative impact, there tends to be a 1-9-90 rule. 1% of the group is highly active, 9% are somewhat active, 90% are passive.
I believe it's safe to assume that similar ratios can be found in incidents like this - 1% or fewer will go public, 9% will go to their colleagues, and 90% will suffer in silence.
And remember, we're talking about cases of negative impact.
Ultimately, I don't think taking the argument down this path of conjecture over allegations (or lack thereof) will help clear our view of what is or is not the reality at the company. That's what company wide satisfaction surveys or platforms like Glassdoor are for. And in both accounts I don't see many signs that Google is doing poorly.
Edit: and the results of investigations prompted by these accusations might shed some light as well.
In addition, we're only seeing this from the perspective of those who feel they were retaliated against because of those protests, with absolutely no additional context or perspective of the managers/execs/peers (which I think we will never obtain for rather obvious reasons).
Personally, I have found Google to have a really open culture of communication. You're generally free to give your opinion. I'd be much more afraid of retaliation from peers due to something I said being considered offensive by some of them, than by an executive or my manager due to speaking out against the way the company does things (which happens all the time and by large amounts of employees). Of course that's just one experience and I may have been lucky with my own team.
disclaimer: I recently joined Google but I'm only aware of these incidents from media publications such as this and everything above is just my personal opinion on the incident.
Edit: Added that "more than a dozen" other stories were shared in the meeting according to the article, as I had originally missed that.