I enjoy your posts very much and have respect for you. But I'm afraid that I have to disagree with you AND your mechanic. You CAN change your oil too often, but it doesn't hurt your engine, only your wallet.
Actually in some applications 2,000 mile intervals may not be near enough. If you are driving very short distances, like a 5 or 6 mile hop to the office, you are not warming the oil enough to boil out the moisture. In this case you need to be changing the oil about every six months or less, rather than by mileage.
I'm still very anxious to hear WHY nad HOW extremely frequent oil changes hurt your engine, except for the extra wear on the drain plug and oil filter bolt threads as well as the hood hinges.