I don't think it's that simple. At the trivial and obvious level, you need to speak a common language. But even if you're both speaking English, you can communicate much more effectively if you have a shared cultural background that you can both refer to.

Okay, language. Check. But at my last two positions, my closest work-partner was from Malaysia and Lebanon. Slight accents, but completely great to work with.

When I'm having trouble with something, the last person I want to help me figure out my problem is an exact clone of myself. I want people used to different tools and different ways of thinking.

that is an extremely macro level of culture that does not explain why there are so few women, hispanics, and african-americans in technology. They aren't that different of a culture. Certainly far less of a cultural difference than all of the H1Bs they're hiring.

You're not getting the point. All of you who keep parroting your master's "cultural fit" line are not seeing the lie for what it is worth. It's not about culture.

so, what's it about then?