The JBS used to be an anti-Communist organization but when the USSR bought the farm, they started getting infiltrated by anti-Semites and conspiracy kooks.
The JBS was always filled with conspiracy kooks. They just happened to glom on to a conspiracy that actually existed, though they overreached and alienated the mainstream of conservatism (including Buckley and Goldwater) when they accused Eisenhower of being a communist agent.
They were always into conspiracy, but they've gone stark raving mad here lately.
I was a member of the Birch Society from 1977- to '81 (the Jimmy Carter years) and I have a very negative opinion of that organization. They are a remnant of the old pre-WWII right wing and have promoted anti-Semites like Nesta Webster and Prince Michel Sturdza. Their worldview is basically the Nazi "Jewish conspiracy" theory with the word "Jews" removed. And while they were all for "US interference" in Central America during the Reagan Administration (the Western Goals Foundation), they are "isolationist" when it comes to any "US interference" that could wind up benefiting Israel or Jews. In my experience they are extremely anti-Israel and not much shy of the old "Liberty Lobby." In fact, my personal opinion is that they operate as the "blue lodge" of the anti-Semitic movement in the United States.
Some of you are going to pile on me, but I've been there!