I suppose it is possible that you could have your run of the mill islamists , like Hatem Bazani, a professor of islamic studies at Berkley.
He only calls for an Intafada in the United States, but never participates in the violence himself. Just like Yassin, Arafat and Rantisi.
Then again you have teenaged suicide bombers who have a change of heart at the checkpoints, and ask for assistance to remove the bomb vests. These would be radical '' nonislamists''.
Also the term radical is usually refering to some unusual action. Like a Muslim waving a tricolor and singing La Marseillaise with a tear in his eye. ''Radical'' would be inappropriate for a muslim who burns an American flag or shoots at Israeli settlers.
So complex . My head is hurting. Think I'll drink a beer.