We are going to be in a lot of trouble if a major Western power ever goes ape the way Germany did only one lifetime ago.
Likewise, if the Syrian uprising were as technologically well-equipped as a large fraction of Americans, the uprising would have been a very short one. Every year we field some 18,000,000 well-equipped civilian snipers in a live-fire live-target exercise aka "Operation Deer Season". This may explain why the US government is keen on disarming citizens of "assault weapons", even though such items are demonstrably less of a societal problem than stairs or swimming pools.
What's the gap between most dictatorships and most western governments look like anyway? Is it mainly Nuclear arms?
Why it is publicly acceptable to talk like Timothy McVey?
1) Institutional cohesion and alignment with population. Many dictators have ethnically homogenous security services - their clan, tribe, whatever. People are loyal to the ethnicity, not the country or institution. That's how you get a nations military killing it's own people. In democratic western countries, the military is much more reflective of the overall population, which puts a check on that.
2) Training. Just because Syria has "jets" doesn't mean they're well-maintained, flown by skilled pilots and employed with excellent tactics. It's very expensive and time consuming to apply the tools of modern war. NATO nations spend a ton of money training their troops to improve effectiveness.
Really, I think the first one is most important. Theoretically you don't get violent uprisings in western nations because democratic governments are more responsive to needs and social composition of the population.