Because of the needed help in bargaining for higher wages and better working conditions.
After the fall of the Ching Dynasty, the Republic of China (RoC) emerged. However it was riven by internal strife. Much of the early years was spent fighting the various warlords. After the death RoCs founder Sun Yat-Sun, he was succeeded by Chiang Kai Shek aka Generalissimo. He spent much of his time building up the Chinese army and fighting other warlords and the Communists. It was effectively strongman politics. Sun Yat-Sun and Chiang Kai Shek were not elected, so in a sense, similar to Communists. Chiang was aligned with the West. Mao with the Soviets. An interesting bit of trivia is that the crack Chinese units were trained by the Germans. They gave a good account in the Battle for Shanghai, although their strength was depleted after that. This is why some Chinese officers used the Mauser C96 aka Broomhandle pistol.
If that would happen they would become a free nation
