One perspective I don't see very often in this discussion is one I heard in the appendices of the revolutions podcast. It is the following: People are moderate or radical in both means and ends respectively. So in ideological conflicts one will find:

Radical radicals: people willing to use means outside the current system (e.g. violent force) to reach radical ends (e.g. communism or fascism).
Moderate radicals: people only willing to use means within the current system to reach radical ends.
Moderate moderates: people only willing to use means within the current system to reach moderate ends and go no further.
Radical moderates: people willing to use radical means to reach moderate ends and prevent it from going any further.

I think this is a good perspective to have when looking at behavior of different political groups.