Well, I can tell you, in Europe Extremist Voters switch without thinking twice between far left and far right.
Methods, Objectives and Goals are the same, just the arguments differ slightly.
Both hate the West, especially the US and Israel, both hate the way we live but without offering a better way. Both want to burn down the house just to see who survives. Only the Arguments differ, the left hate the people running their own society, the right hate the people running other society.
And always remember, Hitler was a National-SOCIALIST.