I have actually made that chart and have put stevia in the "to avoid" column, because I've interviewed some people with FM and some said stevia was not good for them. There were some people who were surprised about that, so I later wanted to move that in "to try" column, but I cannot access this article right now.
It would be very nice from you, if you can tell something about stevia and do you have FM or any other GI disorder.
If you search in Google for "fructose malabsorption stevia", you can see different experiences with it. I was trying to find "reliable" charts made by known FM researchers, but those charts are either not complete or the authors require some sort of registration or personal contact...
I haven't found any theoretical explanation why would stevia be problematic in FM, but even healthy people may have some food triggers of GI symptoms. Stevia is NOT problematic for everyone with FM, though.