I Would Likely Lay Down My Life for Two Brothers or Eight Cousins

The problem is in my opinion we have over-instantiated the narrow version of Hamilton's rule. There is an entire landscape of genetic overlap that is not easily quantified. Selection may have programmed us to recognize degrees of relatedness that do not have names. Over time unfortunately it's very contentious and a lot of people including possibly Dawkins would prefer we spend our time on something else.