The term is not a curse word, though it may sound as though I am using it that way. The term is fully explicated, most recently in the following blog.
I estimate the number of Lefty Fundamentalists at more than ten million Americans. That makes this religion one of the top two in America, right after Catholicism.

Lefty Fundamentalists are a large religious, self-righteous group that is big enough to have many of their own newspapers, television programs, syndicated cartoons and spokespeople.
Check my earlier blog and you will clearly see why Lefty Fundamentalism is a religion, unaffected by reality or empirical evidence.