"Try to hire people you could become friends with" seems like a really bad idea from the discrimination point of view, since people are most likely to view someone of the same race, age, and gender as a potential friend.
Diversity means you don't get trapped in an echo chamber.
Seems like you are using very selective evidence there, or selectively attributing only unsuccessful products to lack of diversity.
It's more of "a person whose unique experience, drive and motivation can teach you something and who's pleasant and educational to be around in circumstances outside of employment contract".
People who come from conservative and religious societies will always be pressured by friends to not make new friends who are of different ethnicities.
Thiel is basically ensuring each company Will become a little Island of segregation and this is what I have seen in the bay area: companies that are 90% Indian, 90% Chinese, or 90% white guys.
I think the effect you're seeing (where many Asians, such as Chinese, Korean, or Indian) are more isolated has far less to do with idealogical beliefs, than it does with multiple factors, such as being immigrants in a country that has typically has had a harder time identifying with their culture as well as a large trend of pushing towards higher education, especially in demanding fields such as medicine and engineering.
But I digress :)
If not, you may be bad at leadership regardless.