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.
That quote about Eisenhower is not a simple issue since:
1) Welsh said it off the record and later retracted it in his published book.
2) Welsh went to great pains to explain that Eisenhower did more to grease the skids for the genocide of 100 million than any other westerner and as such, that made him an agent of communism.
Sounds about right to me - I think anyone that got in the way of Patton was a traitor.
http://www.freerepublic.com/focus/f-news/972500/posts