It's all very vague because Boer can mean an Afrikaaner, an apartheid soldier, or the Afrikaans word for farmer, a cop, or the Apartheid-supporting former National Party.
The word boer also means 'farmer' in the Afrikaans language and, depending on the context, is often a pejorative term for an Afrikaner when used by non-Afrikaners.
Idk why white people get mad at the N word generally being exclusive to black people when they have their own version