I don't know about Pre-war Russia, but communists in post war America were the very definition of social pariahs.
In the pre-war Russia, communists (the Bolsheviks) were simply not a factor - they were a marginal radical group mostly busy with internal squabbles. They had 15 seats in the Fourth (1912) Duma, out of 448. But notice: they
did have those seats. The Left - even the radical Left - had been increasingly integrated into the increasingly democratic decision-making process. Milyukov was not a idiot at all: there was no special reason to think that Russia is not about to join the happy family of liberal constitutional monarchies, like Britain, Sweden and the Netherlands...
communists in post war America were the very definition of social pariahs.
Kind of like the Aryan Nations now? Pobrecitos!
There is simply now way you can honestly claim that pre WW1 Russia was anywhere near the stability of post WW2 America.
Your 20/20 hindsight is duly noted. But the people who actually had to live in the 1950s had no idea they are in the Paradise. They just had experienced a Great Depression and then the most horrible war in history of the human race.
And now they were staring in the face of an enemy even more destructive and inhuman than the Nazis and the Tojo militarists. You and I both wish they would stay calm and rational, and angelically fair, under the circumstances.
But could either of us actually be that impartial? In the real life?
Russia had been crushed by Japan on the battlefield, had a revolt that forced an unwilling monarch to share power and revolutionary socialists winning a large quantity of seats in Parliament. Even without WW1, the situation was clearly a power keg.
It was "clearly" - and mistakenly - not.
The Russo-Japanese War was an imperialist adventure 99 % of Russians could not care less about.
On the level of the politically engaged 1% - Yes, it was a blow to the throne's prestige, and yes, it did help to push for the democratic reforms - very much like the Crimean War defeat did help with the liberal reforms eventually leading to the end of slavery under Alexander II.
But that's the point: Liberals, moderate (constitutional) monarchists and socialists (of the non-mass-murdering variety) did acquire a lot of political power between 1905 and 1913.
Nobody - including Lenin (mostly frolicking in France and Switzerland - thankfully, money was no object) - had anticipated the catastrophic events of 1917. It was a "red swan", so to say.
P.S. You are not quite right about the influence of the Socialist Revolutionaries in the aftermath of the 1905 troubles. In the Second Duma, they had about 40 seats; liberals (the "Constitutional Democrats" of Milyukov) has almost a hundred, and unionist Laborites had more than that. They had their moment later, after the February Revolution.
