Iranian history is even more complex than Afghanistan (since Iran is actually worth fighting over; Afghanistan, not so much). Even though the Shah was a pretty good ally of the US, I'm not sure whether the Qajar dynasty vs. others who came after him were better/worse. The semi-communist guy who Anglo-Iranian oil hated (and the US stupidly followed the UK on) might have been one of their better leaders of the past 200 years.

I agree the people who turn into resistance are often extremists, and if they win, can become more powerful. But there are plenty of cases where resistance fighters came from other organized groups who weren't particularly psycho to begin with; Balkans, Arabs during WW2, etc. Organization and logistics probably trumps insanity in predicting whether a group will be effective, as long as the occupier is brutal enough that everyone hates the occupier. Sure, plenty of the leaders and groups were utterly insane (Arkan's Tigers...), but I don't think it was universal on any side.

(btw, this is kind of an interesting tv show that I'd never heard of before! I'm doing some mindless paperwork right now so it's entertaining listening to a somewhat-psycho marxist making more sense than the other people at the table, oh the irony)