Well, “radical” Islam is really a cop-out. Islam has been sprouting one form of “radical” Islam or another since its inception.
The fact is Islam is the problem - ALL of it.
A “religion” of hate, brutality, intolerance and violence, created by a slave-trading desert bandit for slave-trading desert bandits.
There might be something to what you say. But maybe not. Consider fascism. You had the Hitler variety, the Mussolini variety, and the Franco (Spanish) variety.
The Hitler variety was, of course, the most radical. Hitler had to go. But the allies left Franco alone, and rightly so.
Here's the sad thing. FDR to stopped at nothing to rid the world of radical fascism. But Bush II preferred to just play whack-a-mole with radical islam.