I don't agree with OP. I'm American and have mostly worked for American companies and have rarely had issues with giving honest, often difficult, feedback to superiors.

But

> 80% of your peers are Chinese and Indian H1Bs who bring that culture of deference to authority into the US.

is sadly spot on. Even when the org is very receptive to feedback, one manager in the chain who possesses a cultural belief in absolute authority is enough to break the feedback chain and lead to an organizational abscess of festering dysfunction.

It becomes even worse when your org's management has been taken over by a single cultural group and there is no one to turn to and your only option is to wait for the org to implode and be restructured from above.