So, you have the working class split four ways: union bureaucrats, old union members, new union members, non-union members (rest of working class). It all just kind of plays out Gould's remark that he does not have to fear the working class because he can always get one half to kill the other half.
One half could be black; the other, white. One half could be union; the other, not. Etc.
Joanna