Actually not. The employer and employee signed a contract, one just a legally binding as any other.
Whether it was responsible or not is another matter.
I agree with the fact that the UAW signed a contract, These are not UAW workers. They are white collar workers. They are not protected by a union contract. Many of these workers where employed in right to work states as at will employees and are not protected by labor contracts.
Regardless all of the retirees union or sallaried are not first tier lenders in a bankruptcy. They have no security against the auto companies.