It certainly helps that they've protected themselves from the ability to "delete Google" with an embrace, extend (or buy), extinguish[0] strategy when it comes to the technologies at the core of the modern web.
0. https://en.wikipedia.org/wiki/Embrace,_extend,_and_extinguis...
What? Protesting from within perfectly sends the signal that it’s still the best place to work despite egregious offenses.
Why must that -- and nothing else -- be the signal they're sending? People have a variety of motivations.
For example, I left my country 20 years ago because I wanted a better future and I had no desire nor conviction to stay and try to make that future happen there. Of those who stayed, most had no other choice. However, there's a non-negligible number of people who stayed despite having opportunities to leave, precisely because they are willing to fight to make things better.
Moving in general is difficult, but leaving a country and permanently moving to another one is infinitely more difficult than finding another job for someone who works at Google.
That's precisely why I wrote "of those who stayed, most had no other choice". I understand the difficulties inherent in moving from one country to another, as I've done it twice now. The difference between changing jobs and changing countries does nothing to invalidate my claim that people can have different motivations and that one of them is "I wish to stay and fight for this cause in this place."
They do not have a monopoly on talent and they are actually fearful of being no longer seen as the #1 workplace option for top candidates. Protesting as a Google employee gives you much more leverage than an outsider will ever have (unless you have the $$ to buy off a handful of senators).