After reading all 544 posts while it was going on I would say because they were unprepared and should have turned back when she first hurt her paw early on. By the time she was completely lame it was to rough for them to pack her out.
Then the jerk made no effort to organize a search to go back and get her. He left that to others who did so.
If you read the whole thing you will have no sympathy for him at all.
I would’ve died trying...but that’s just me.