Upvote:6
The disarmanent theory would seem not to be the case. That's because Stalin's agent in China was one Mikhail Borodin.
Up to about 1925, Stalin, through Borodin, had maintained a fairly even-handed policy between the Nationalists and Communists in order to keep them in a "united front" (against the warlords). By 1927, Stalin and Borodin were tilting "left" on the Chinese scene. That partly meant being "pro" Communist, and partly favoring leftists in the Nationalist Party such as Wang Jing Wei over Chiang Kai Shek. The uprising in Wuhan appears to have been part of this strategy.
Stalin never had the power to "disarm" the Chinese Communists. What he could do was to stop the flow of arms to them, but it did not appear that he did so. If any Communists "disarmed" the workers in Shanghai, it was not Stalin but the local Chinese Communist party, although most of the actual disarming was done by the Nationalists under martial law. There may even have been a misunderstanding, whereby an order to restrain the Shanghai workers (from e.g. attacking foreign property) was misinterpreted as an order to disarm them.