What's Scary About the Christian Front?

The Christian Front nearly executed a plot to overthrow the government in 1940. They had heavy machine guns that they had stolen from the US military. The FBI believed they were within a week of starting to set off the bombs when they picked them all up. And then they were acquitted. It wasn't some neo-Nazi fringe group standing on an overpass in Florida, right? This was a group that had a lot of community support.