Even in Mao-era China, it had dog-shit foreign policy and was relatively non-interventionist besides helping with the Korean War on its border. The Sino-soviet split was broadly on the lines of opposing the USSR's "social-imperialism", I.e. their interventionist foreign policy and dictating of who gets revolutions and support for revolutions, and how their post-revolutionary government will look and function. China and the USSR had a number of border skirmishes because of this, and Mao-era China resented Stalin's government for telling both China and Korea they would be getting no support in their revolutions in order to kow tow to the west.