Cú Chulainn, also spelled Cú Chulaind or Cúchulainn and sometimes known in English as Cuhullin, is an Irish mythological demigod who appears in the stories of the Ulster Cycle, as well as in Scottish and Manx mythology. He is believed to be an incarnation of the Irish god Lugh, who is also his father.
Trying to imagine if an African folklore hero was played by a blonde white guy. There would be outrage. But erasing white Irish history is fine.