Yeah, it's not a great choice either way. Certainly the GA should not have made a public scene out of Mr. 6A, but the greater good was served by bouncing someone, anyone, rather than waiting to negotiate a volunteer.

I highly doubt that the crew went illegal out of spite. There truly was a huge time pressure and they were trying to get the flight out.

Finally, one last thing, and I know it doesn't make a ton of difference, but you didn't interact with one United Airlines employee during this whole debacle. Now, I say that I know it doesn't make a difference, because United is repsonsible for whom they force you to deal with. However, the reality is that switching to another mainline carrier will mean you'll still be working with the same feeder carriers, just dressed up in different uniforms.

None of this excuses what went on. If I were you, I would email a ton of people about this unbelivable display. It's the only way you can contribute to this person's termination so they won't inflict the same treatment on you or other passengers again on any UX/AE/CE/etc. flight.