Quincy, you are correct that proctitis just means 'inflammation of the rectum' which of itself doesn't establish cause, with there being a number of causes for proctitis including:
https://www.healthline.com/health/proctitisWhat I was saying to Candoolili is that in the UK gastros tend to say 'proctitis' to mean proctitis caused by IBD rather than being specific.
The Crohns and Colitis UK link I referenced was to demonstrate that they also use 'proctitis' to mean proctitis caused by IBD. On their website they state: "The inflammation usually begins in the rectum and lower colon, but it may affect the entire colon. If Colitis only affects the rectum, it is called proctitis."
My intention was not to imply you were incorrect, but to point out to the OP that in the UK at least gastros don't tend to say ulcerative proctitis even when they mean ulcerative proctitis (and perhaps should say ulcerative proctitis).
Candoolili will hopefully find out the cause of their proctitis at their follow up appointment.