BUT, the very people @Prunebutt cited were advocates of violent changes to established oppression. Their critiques of the Bolsheviks stemmed from ongoing mismanagement and oppression.

Contemporary America had very similar civil rights violations, with the main difference being that the US government was an established authority, while the Bolsheviks were only recently established. Attempting a worker's strike in the US got people killed; attempting something like the Kronstadt rebellion in the US would have been an even worse bloodbath than the original.