The USSR wasn't seriously contesting colonialism, especially not internally. But the very processes of imperialism produced classes and castes that generated people who would contest colonialism; and, they produced population booms and a bias towards a moment when well organised light infantry supported by artillery especially in close terrain; and, the Comintern and Cominform provided organisational structures and techniques which were exceptional at mobilising the potential new classes in the periphery of imperialism. For India one may consider the British response to Chinese imperial bureaucracy. For China, one may consider the Chinese response to Chinese imperial bureaucracy amplified by the comintern. Not so much the Comintern/cominform as a particular ideological centre, but as an organisational locus. In someways these are just the Interregnum in England, or the French republic and empire with better literate bureaucracy. Without the Comintern, similar people would have found similar techniques wherever they could. WWII did stretch the capacity of imperialist states, and amplify the anti-imperialist techniques in the periphery. But a similar macro-economic catastrophe was implicit in the emergence of high fordism. About the only escape from anti-imperialism is a low-equilibrium trap like a depression forever that doesn't produce a nexus of social and cultural influence. But that just gets us a great China's 19th century across imperialism as a world system.
Hate to be overly macro-economic: but some locality of imperial capitalism in the 1930s would refuse a low-equilibria trap, and create the crisis of 1940-1990 in the ability of the leadership of empire to maintain policing in close terrain against high-populations with literate new-classes and an ability of these new-classes to mobilise bureaucracy better than the centre of empire.
If not Indo-China then India, if not India then China, if not China then the East Indies, if not the East Indies Afghanistan.
yours,
Sam R.