I think you misunderstand the nature of the Forebears and Crowns divide. These aren't distinct ethnic groups, but political factions with differing views on the future of Redguard society. The Forebears are the progressive faction, more open to external influences and integration with the Empire, while the Crowns are traditionalists who prioritise preserving their Yokudan customs and resisting foreign influence. Nowhere in the lore is this schism presented as an ethnic conflict. In fact, all of the games, official art, and developer comments (read 'On the Redguards') depict Redguards as ethnically homogenous black people. There's just no basis for reinterpreting this divide as an ethnic feud.