It's hard not to overlook the fact that a lot of would be immigrants make no effort to assimilate and cluster themselves off from mainstream society; especially in a immigrant welcoming area like Silicon Valley. I bet if you were to go to China/India etc., no one's going to go out of their way to accept you.
(BTW, I'm an Indian citizen on H1B and I'm saying this, you can downvote my post but it doesn't change ground realities)