If you are just venting on here as a "safe place" to be able to vent, that's one thing. You are biting the hands that are trying to help, but I can understand wanting to vent somewhere. If you even give a hint of this attitude when it comes to applying for a position for next year, it will come back to bite you. You are in a position that you now have the additional red flag of leaving a program.
Yes, you are unhappy about the situation, but it is what it is now and you need to do your best to make that situation not hurt you to recover your career. You can expect that ANY pd will want to talk to your past pd, regardless of the letter you have just because of the nature of the situation. You want to remain on has much of your old PDs good side that you can to try and make it easy for you. In hind sight, no, you should not have lawyered up. Your career is not gone at this point, you do have a chance to recover. The lawyer option shoots that one away.
As for it be unjustifiable, in almost all instances where this happens, there is more to the story. There is a good chance that there were problems with your performance that you did not have the insight to be able to see for yourself. You don't know what you don't know. Maybe they could have provided better feedback. Maybe you could have solicited more feedback during the rotation. I don't know, I wasn't there. Going forward where all of this is someone else's fault and you have no blame will NOT help you find another position. As
@gutonc said in another thread, you need to go with your tail between your legs and look for those new positions. Don't blame others, don't make excuses. Just go out there and find a position that allows you continue to become a board certified physician.