When I hear Nazi I think of concentration camps and killing Jews. Kirk was a big supporter of Israel.

Well, Israel didn’t exist when the NSDAP did, so if you apply the literal meaning of each, a Nazi couldn’t support Israel. But fascism was also something that only applied to the party in power in Italy from 1922 to 1945. The terms have somewhat evolved since then; fascism generally meaning authoritarian, ultranationalistic and antiliberal. The same applies to nazism, but usually with some racist ideology with hatred for other religions.