As an ex-RAF Recruiter, I can say that that Recruitment staff cannot comment on individual cases as they are not qualified to do so. I had an RAF Medic in my office and even he couldn't make comments such as have been made to you about 'easy to appeal'.
You need to check exactly what it says in your medical records and get written evidence from professionals in support of anything that is incorrect or that has changed. Your own GP, for example, can't say you are fit enough to join up; they should only comment on your personal situation.
Medical standards for the Armed Forces are written based on research into conditions and the chance of another occurrence, causing harm not only to a candidate, but those around them during training and working. They aren't going to take the risk on someone suffering a debiliting injury and/or failing on a task, whether on exercise or operation.