I also don't happen to agree with USAPA's whole reason for being. I am sure you will come up with many other reasons, but you know the main one and won't even begin to pretend it is anything else- keeping the job I brought to the table.
It would be hard to label the "straw that broke the camels back" as "the main one". It was one of many straws. By itself, it would not have caused USAPA. It was a part of the whole concessionary package.
After all, far and away, most of the pilots at US stayed on the property because DOH was assumed to be worth something. Aside from putting up with concession after concession (mostly unnecessary), the "nic" tried to take one more concession, turning twenty years into three. The beneficiaries were 1800 pilots at AWA and some executives, all led by a drunk.
Were the concessions to lead to the ability to fly forever, minimizing the insult and/or more aircraft than even god can count, a different path might have been available, but to take away an irreplaceable resource, seniority, as in number of years, on top of the lowest compensation levels in history (adjusted for inflation), the loss of retirement and, for many, massive downward changes in benefits and to package the new structure as "relative seniority" when it was not even close, was just too much.
It is not all of ALPA's fault, despite providing incentives for lazy pilots to ride the cushy FPL vehicle. It used to be management that provided a place for those not wanting to fly or, in a few cases, those who should not fly. The union opened up some possibilities for those folk but that was not all. For instance, the east pilots allowed the shuttle dudes to stack the MEC, setting up a situation for them to access the pilot retirement, in essence, double dipping. But, mostly it was electing weak "leaders", people who, on witnessing one or two pilots with their hair on fire, would, in turn, set their own hair on fire. While I really cannot "blame" ALPA for some of this, the pilots were depending on ALPA, as franchisor, to keep some sort of reasonable order.
I don't blame Captain Prater for doing what he is doing. He is simply following advise from his lawyers, hoping to minimize the damage, though his "loyalty oath" thing, born from the moronic CLT reps, guaranteed disgust with ALPA forever. (Sometimes I wonder if Captain Prater secretly thinks ALPA needs competition.)