As another former paramedic I completely hear what you are saying. I can't even begin to count the number of times someone has made the assumption that I'm fresh off the turnip truck just cause I wear a short white coat and therefore am totally incapable of performing even the most basic tasks (IVs, etc..). At, first I would try to explain that I had been a paramedic for 5 years. However, this seemed to come off as not taking criticism well or arguing with nurses/attendings. Even if they would understand it kind of just made the situation awkward. Plus, I don't think most people, even a lot of ED docs, really have any idea what happens in the prehospital environment. Add to this the fact that physicians don't really recognize any other type of medicine as being legitimate if it is not delivered by a physician. And to add to what Arcan alluded to, a lot of us do have issues with attitude. I know I had a horrible chip on my shoulder when I worked on the ambulance because that is the ONLY way to function. If you all think cynicism is necessary in the ED spend some time on the streets! But, alas I digress. What I'm trying to get at is that as much as it sucks to not get any credit for the knowledge and skills and service to your community, blah blah... I think your best option is to just let everyone think this IS your first rodeo and just grin and bear it. If people want to think you're an idiot just let them, deep down you know what you're made of.
The irony here, for me anyway is that when I'm honest with myself one of the main motivating factors for going to medical school was pride. I got tired of people judging me based off of my educational credentials. I wanted to prove to everybody that I was just as smart as they were! So, I left my awesome life where I was living in an awesome west coast city, surrounded by family, making good money, doing tons of hobbies I loved, with my fiancee, and moved to BFE where I'm freezing my ass off and have accrued 270K in debt. Yeah, I really showed them how smart I was! Not.
Pride, is indeed a very dangerous emotion.