The crazy part about this is how little similarity it takes to fool us.

But those people are in fact related. If you could test their genetics, you could prove it. They have different variations on the same face that some successful ancestor of theirs once had long ago, which was conveyed to them in their own generation over hundreds of years by the inheritance of dominant genes.

You will find that people who have such similar faces also tend to think and act similarly also. Not a coincidence.