It is frustrating, and I completely understand where you are coming from. Most of us have and will continue to encounter ignorance in the medical profession. I'm still my GP's only patient with a pouch, and while she has made an effort to learn, now over 4 years out from my surgery, she clearly still has a very poor concept of what typical norms and expectations are for pouchers. Last year she told me that going to the bathroom 4-6 times per day was far too much and I should see a GI immediately. She also continues to ask me at my yearly physical about "flares." *faceplant* It's hard to remain patient in such situations, but on the flipside, I try to make it my goal to educate health professionals about life with a pouch whenever the opportunity arises, as some doctors are actually quite interested and will ask you a lot of questions. I see that as a bonus on both ends; the doctor learns a bit, and it might actually help them focus a little better on my care instead of going off on 18,000 tangents irrelevant to what the purpose of my visit is.
But obviously it doesn't always work that way, and understandably, there are doctors who are not willing to admit that their knowledge may be inferior to a patient's. The only other thing you can do is literally have your surgeon or GI call the rheumy to discuss your situation. I have had my GP talk to my surgeon once before. Often doctors are more willing to accept "education" or information from a colleague physician rather than a patient. That said, I haven't ever been able to shake off the diagnosis of UC either. It seems once you have UC, you're always labelled as such, colon or no--though considering that you can have other manifestations even after the colon is removed, that is probably accurate.