United pilots beef with ALPA really isn't about the RJ pilots themselves but the fact that ALPA allowed management to hand over our jobs to the RJs. Not the RJ pilots fault, not by a long shot.
Bottom line, I really can't come up with anything that ALPA has done in recent years to protect United pilots but I have seen plenty of things that have thrown us under the bus. Age 65 being one of the foremost. As for voting with your feet, easier said than done. US Airways mostly stepped out due to the divisive nature of the pilot group.
I think we at United suffer from learned helplessness. We have been beaten down for so long we have not just forgotten how to fight but don't even realize we can fight. I'm not claiming to have any answers but I hate to see pilots becoming pitted against each other, it does not do anything good for us in the long run except distract us from the important issues.