Why were klan members terrorizing the lumbee in the 1950s?

Racial hatred
The members of the clan were motivated by racial hatred. The Lumbees however outnumber the Klan members who were trying to put a damper on them and chased them downs with guns. The lumbees are native Indians descendants of the Chi raw native Indian tribe .

They were constantly being overlooked as a people and were being controlled by people who weren't really native to their homeland.