Your thesis really doesn't hold up to history. The Nationalists were winning the Chinese Civil War until WW2 put the conflict on hold. Had Chiang Kai-shek made a few different decisions, there would be no communist China.
The British never controlled China anywhere near the degree they controlled, say, India. Their presence didn't penetrate beyond the coastal provinces (you can see this in that the Chinese presence in other British colonies was largely Cantonese/Fujianese). Even Japan never managed to control more than a section of the country.
The Chinese civil war is legitimately (not euphemistically) referred to as a civil war: Elites battling for control as the center weakened.
I'll agree that the use of the British as a propaganda foil was somewhat effective, and legitimately pointed out atrocities and unfair treatment by all the foreign powers involved. But the value of that propaganda (still effective today) was disproportionate to the actual influence. Nothing wrong with that by the way: state building always involves such propaganda.
By contrast you can see that Britain fully controlled the Indian economy (though for many people lower down on the feudal hierarchy the British were merely one part of the control system, essentially trading one prince for another). And, like China, Britain was one in a punctuated string of foreign invaders who displaced the remnants of a fading prior system. "Indian" identity was more a construct of the educated upper classes who were able, in the 20th century, to eject the British.
the british didn't need to control china in any degree for this to happen. just some greed at the wrong time, in the wrong manner.