So often I encounter an implicit categorical claim where one is unwarranted. As an abstract matter X's are good, the narrative goes; x is an X; therefore x is good, and attacks on x are bad.
Unions, the capacity of workers to bargain collectively, are essential. An army is also essential: indeed, according to the Catechism every person has an obligation to defend his country.
From neither of these abstract facts does it follow that a particular war or particular union or particular union contracts are inherently good and just, and insulated from criticism. People should not argue as if it did follow.
Setting aside the anti-South anti-white bigotry, an unstated assumption in this post seems to be that it would not be good to kill the UAW off completely. I don’t have a position on whether it would or would not be good to kill the UAW off completely; but it cannot be taken as a simple given that the UAW is a good concrete and particular institution, worthy of support and survival, just because it happens to be a union.