Back then, people who supported workers' rights were often called commies by their opponents.

commies 是名词 commie 的复数形式，commie 是 communist（共产主义者）的俚语或贬义称呼，带有贬低或敌视的意味。这个词在冷战时期尤其常见，用来指代支持共产主义或社会主义思想的人。