If memory serves, there were two unions Hostess was negotiating with. One represented most of Hostess' workers and was negotiating in good faith. The other represented a small percentage of Hostess' workers, and was willing to sacrifice their members at Hostess to gain an advantage in their negotiations with different companies who had more employers.

Arguably, this is a reason unions shouldn't get too big. It creates scenarios where some workers get their interests sacrificed, precisely the thing unions exist to forestall.