Strikes are not the main way workers fight for better conditions for themselves in socialism, the society as a whole is oriented in a fashion where this is achievable by reform and referendum, democratic institutions. Strikes can and have been used by western, anti-communist groups against socialist systems, and this is what's illegal. You're again falsely pretending the PRC and US Empire have the same economic system, and thus mechanisms like strikes have the same utility in each, but that's not the case. Strikes are more useful in capitalist economies where the state is on the side of the capitalists.
During the cold war, the anticommunist ideological framework could transform any data about existing communist societies into hostile evidence. If the Soviets refused to negotiate a point, they were intransigent and belligerent; if they appeared willing to make concessions, this was but a skillful ploy to put us off our guard. By opposing arms limitations, they would have demonstrated their aggressive intent; but when in fact they supported most armament treaties, it was because they were mendacious and manipulative. If the churches in the USSR were empty, this demonstrated that religion was suppressed; but if the churches were full, this meant the people were rejecting the regime's atheistic ideology. If the workers went on strike (as happened on infrequent occasions), this was evidence of their alienation from the collectivist system; if they didn't go on strike, this was because they were intimidated and lacked freedom. A scarcity of consumer goods demonstrated the failure of the economic system; an improvement in consumer supplies meant only that the leaders were attempting to placate a restive population and so maintain a firmer hold over them.
- Dr. Michael Parenti