这句话是完整的.只不过看起来不想是纯正的英语.应该是咱中国人写的吧.即使你把that 换成了where 它也不是状从啊.stems from 起源于,是一个词组.你前面理解的对,后面就这样想吧：racial prejudice is generated by capitalists as a means of controlling workers.是对capitalist system的修饰.不过,说到where,我个人感觉也有道理,可以看做in which,句子翻译也很通畅~