Have you ever been a devout practitioner of a religion whose views on the world differ in key parts from the established scientific consensus?
Have you ever been affiliated with a political party that was highly popular (or a monoparty even) in your country but was held in contempt by the rest of the world because of how totalitarian/inhumane it was?
In both cases, you could read whatever, even critical information about your values. But you would have an explanation ready — enemies envy and slander us, they either know they lie or they are repulsed by the God's light because of how corrupted they are, they are not aware of the whole truth... You would have a whole arsenal to explain things away, because you are committed, and your commitment makes it hurt to realize that the purpose your values serve is not very noble, or that you're a part of something atrocious. It's the human nature.
I understand what you’re getting at and there is certainly a lot of closed-mindedness going around. I don’t think any organization is immune to this.
But there are also a lot of employees who have strongly opposed various Google policies and engaged in various political activity based on that, so the groupthink doesn’t seem to be working very well? Also, the company leaks like a sieve these days.
Even before that, there were a lot of internal debates. (They just didn’t leak as much.) It’s in part because of these debates that you need policies; people sometimes say careless things in heated discussions.
When a company is large enough[0], it's probably not unreasonable to start thinking of it as a municipality, or even a small country. There are probably people who live in my city who I wouldn't like, there are probably policies of my city I don't like, but I still live where I live.
Similarly, at a large enough company, if your work is good, but some other division of the company is bad, should you leave the company(city/country)? Or just avoid the bad division?
[0] Leaving aside the question of whether it's a good thing for companies to get that large.