What we are dealing with in the middle-east are dictatorships that keep a lead on ethnic tensions, very much like in Yugoslavia. I would expect that any diplomat would have predicted tensions between Sunni and Shia in Iraq. Exactly like similar tensions exist in Saudi Arabia and will most likely blow up if the regime becomes unstable.
Well, there's just one small issue: people. Have you met them? Do you honestly think that inhabitants of North in South Korea actually want to live together as one country? That southerners want their first-world economy to support the shit-poor north for several decades? That northerners want all their lifestyle and ideals that they have been taught from the crib, destroyed? That these people are ready to trust each other in general? Hell, even northerners who defect and run to the South encounter a lot of hostility — can you imagine what the shitstorm happen when millions of them will cross the border in search of better life?
In the 1900s, Russian left wingers were educated, nuanced people who were trying to lead the country to a brighter future. 20 years later, Russian left wing consisted of ruthless fighters who burned down entire villages, performed brutal performed mass executions of thousands and built the biggest terror machine world have ever seen. These were, for the most part, the same exact people.
That's a drastic oversimplification. The majority of the Russian Left was made up of SR (which later split, but for the sake of it they can be treated as one group), and the Mensheviks. The Bolsheviks split the Russian Social Democratic Labour Party (with the other part being the Mensheviks) roughly down the middle, but the moderates outnumbered them substantally.
Already shortly after their coup (the czar was arrested in the spring; the interim government was SR led from the summer; in November the Bolsheviks decisively lost the election to the the Constituent Assembly, and that's when they struck - there was no revolution, but a coup d'etat against a more moderate socialist government that had the support of the people), the Bolsheviks started getting rid of the parts of the Russian Left that had opposed them, and soon groups were actively fighting them in the civil war, while others were fighting to stay out of prisons or to avoid being killed, and some forged uneasy, temporary alliances in the hope of survival. Soon their parties were illegal. As Stalin gained control, the purges intensified, including purging the Bolshevik party itself.
The Russian left changed because the moderates (including communists/marxists) were imprisoned or murdered for opposing the Bolsheviks, until there were hardly any left.
The Bolsheviks, or at least their leadership, largely remained the same people, but in 1900, and all the way to at least 1917, they were by far outnumbered on the Russian left by their future victims.
That was my entire point — people who are saying that US was funding future Al Quaeda in the 80s are just as wrong in the nuance but are just as right in general. Bolsheviks were the logical conclusion of radicalization of the left. Revolutions devour their own children, after all; just like Mensheviks, just like the _real_ democracy-loving anti-Assad protesters. All of them either die, or become the radicalised, grotesque and horrible plagiat of the original.
Imagine that right now, on some point of the globe, there's a popular rebellion against a dictator who is, without a shadow of a doubt, suppresses the people, kills his political opponents, and tries to indimidate other countries of the region with his military machine.
Hell, just imagine it in North Korea (but forget about the big China brother for a second, to make this situation a more simple example).
Would you honestly tell that you support the dictator in this conflict, because otherwise the whole situation will turn into a bloody civil war, and he's the only hope for stability? That when those western-looking, english-speaking, democracy-loving rebels are gassed and killed, western states should not intervene?
Well, may be you are — but then any website with political hivemind similar to HN will downvote you to the oblivion.
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You also may be forgetting one other factor at work in the Middle East — Russia. While it's not USSR kind of superpower it once was, it still has deep ties with arab world that it nurtured for the whole second half of twentieth century. It had established good relationship with many authoritarian regimes and terror groups in the region: Khomeini, Hezbolla, Assad and Hamas. And dichotomy of "chaos vs dictators" is exactly what Russia wants for Middle East: dictators are easy to deal with, they're much more ineffective as oil producers, and, of course, the whole dilemma greatly legitimizes Russia's own political system as well.