GooberDrake, I tend to agree with your assessment. The problem is when tests all come back 'normal' or near-normal, docs are hard-pressed to try to help and it can become a problem for you and your doctor to try to figure out what to do. He may be turning to the only thing he can find on your chart to try to offer some help.
You're saying you've always had problems with diarrhea, bloating, etc. Are there any other members of your family who have experienced digestive issues? Do you get any rashes or blotching? Any signs of 'brain-fog?' Or how about fatigue that is either lingering or can hit like a 'ton-of-bricks?'
I'm wondering if the problem you're experiencing might be related to any form of food intolerance. I know it seems strange to think that food could 'poison you,' but in many individuals it does and it can be hard to track-down the offending food group. But there are some tests you might want to consider.
With foods there may not be a one-to-one 'cause-and- symptoms-immediately-appear.' Sometimes the effects can take hours, days or weeks to show up. And with long-term exposure it seems like anything you eat can create low-to-high-grade misery.
I had thought about food intolerance or even allergies and had talked with my allergist about testing for food allergies but he said he didn't want to test for those at the time. That's kind of what made me finally go to a GI. I don't have any rashes or blotching or brain fog. I do experience fatigue most of the time and never feel fully rested. I had pretty much summed up that that was a side effect of whatever stomach/digestive issues I have. I do know I can't have milk though cheeses and yogurt don't generally bother me. Super dense rich foods tend to irritate the issue as well. I've also discovered that I have to stay away from anything that contains sucralose as it makes me almost violently ill. And recently I've started a no/low sugar diet eating low carbs and only whole wheats. I'm still having digestive issues after 2 months on the diet and am still having trouble loosing weight. I also carry very dark circles/bags underneath my eyes which I had also summed up as a side effect of my issue. I will definitely pose the food allergy question to my GI when I see him with all my questions and see what he thinks about that. Thanks for the thought!