Amusingly I found that in Tokyo bars (in friendship terms) I had more in common with the locals than with caucasian Americans with whom I share the same European ancestry.
Nevertheless I am broadly drawn towards females who are similar to me. Those who look most dissimilar do not rate on my "wish to procreate with" list.
For the article's hypothesis to work, it's the second point that matters most. It means that the people who are born around you will be more like you and so are there for available friendship.
Not everyone is like me, and I'm glad of that. The more diverse the gene pool, the stronger the specie.