Choose a word that isn't normally used in a derogatory fashion.
"Hey Erma! Look at those goddamn radicals protesting in the street!"
That type of usage is quite common.
By you automatically associating Fi with being "radical," tells me you harbor a bizarre stereotype - consciously, or unconsciously.
Is there a word that describes someone who holds divergent, intransigent political beliefs that isn't connotatively laden, for good or bad? I personally respect some radicals far more than some centrists.
I come from a poli. sci. background. "Radical" as I'm using it is simply a descriptive term - one who wants changes from the roots (radix, Latin). You're looking for something that's not there.
Please discuss the topic further, and assume good faith on my part.