That call of a shoulder separation on the basis of that xray is a very soft call. I don't think you can confidently call it unless you do ab/ad-duction views. Plus you didn't mention that they "rushed" you to surgery because of your spiral fracture, not because the ER doc missed the shoulder separation, which doesn't require surgery at all.
Most ER docs know what they are doing, including me. Don't be mislead by follow up docs eager to try to prove how incompetent ER docs are just to make themselves look better. Believe me, this is a common occurrence.
That is a nasty fracture though. Must've hurt like the dickens. Heal fast and get back out there!