that the %, non Anglo appearing SEALs corresponds to the general populace in the Navy and the duty designations. Ex: 100 Reg navy  snipers, 12 non Anglo in appearence whereas  10 SEALs, 1 non Anglo sniper. IMHO the SEALs repressent well deserved  elitism, ( as the book by Dick Couch asserts)  but no more so than a Yale degree and  rich daddy. There is probably  a higher  % of  non  Anglo appearing  SEALs than % of non Anglo fortune 500 CEOs. 
Now does "naval " or military culture in a whole actively  encourage SEALs/SOF by non-Anglos.
Probably as much as the American society in "general" encourges women in the scientific fields, but I guess it would be more of a question for Rummy-poo. 
I have heard that the ARMY Rangers are the most racially diverse, but maybe Tom can verify this?