Busboy, from what you are saying, it sounds like ALPA did both. Made sure that retired pilots couldn't return, but made sure that back seaters/pretend back seaters (ie, on leave back seaters that never went through training) were able to return.
However, I'm not sure why that is all fine and good with you. I feel confident that they could have ensured that both the retired pilots couldn't return, and back seaters couldn't return to the left seat of a widebody, causing the rest of us massive career stagnation. I am also most certain that that was what the crew force desired.
Why do you think they couldn't have done both? That's what WE wanted, wouldn't it be their obligation to follow their membership's desires?