I never said Somalis are mixed I said Oromos are mixedOromos have Omotic (Southwest Ethiopian) and Sabean Yemenite (from the early Habesha invasion) admixture not found in Somalis. It is easy to tell pure Somalis from those admixed with Oromos from genomic data.
The majority of ethnic Somalis are 0% Oromo, especially in Somalia proper (excl. Ethiopian Somalis).