The situation can't improve while the USA are doing everything they can to antagonize these places, isolate them, alienate them from their neighbors. Seeing ruthless authoritarians prevail there is completely expected.
"it's purely a reaction to the authoritarian regime of the Shah previously used to further American interests"
Seriously? THAT is what you think Khomeini wanted and his grandson or whoever wants now?
"And same goes for Cuba, Venezuela, etc."
Oh, you're a "communism really only ever wanted good things for it's people, and it's America's fault they started shooting their own citizens" ... got it.
But Cuba and Venezuela govts deserved what they got, and it was plenty of our business being in our backyard.