It's the same that ultra right or neo conservatives have more in common with ultra left or communists or ultra religious groups that go for political power. It'

It's the same that ultra right or neo conservatives have more in common with ultra left or communists or ultra religious groups that go for political power. It's the extreme that makes them understand and appreciate eachother (or their cause) better. It's not that they like or support eachother, but knowing how the other thinks makes a difference. For them it's much more difficult to understand how moderate left or right works and can be influenced. There's a good chance that they fear "moderate" people more than those on the opposite end of their thinking, simply because they don't understand them.