Our culture is accepting of Half-Somalis with Somali Fathers to solely identify with their Father's Ethnicity because our Ancestors were aware of the inevitability that some Somali Men will marry foreign women. Bearing in mind, in the Ye Olde days Children of Mixed Parentage across the World would usually go with their Father's identity.
This also applied to the Jewish Men who came as Slaves to Roman Italy/Europe as they were surrounded with European Women & decided to procreate with them. Hence why Ashkenazi and Sephardi Jews have European ancestry on their Maternal side because their ancestors knew that Ethnic identity could only be passed on through the Father's side.