My digestive system has been screwed up since I was a kid, so I think I have a predisposition for food intolerances. I have a ton of them (many of which are irrelevant with this WOE, thank goodness), fructose malabsorption included. I did a fructose elimination diet a while ago and found I don't tolerate it either. After I cut out all fruit and higher fructose veggies (for a couple months), I started gradually adding fructose-containing foods back in one by one and found I was supper sensitive. I had a reaction after any sort of fruit or higher sugar vegetable (like carrots) I tried.
I think most people can tolerate the small amounts of fructose in fruit. I think after a person clears their system of it, the reaction to fructose will be more pronounced from their perspective because they've gone thirty days without it. Once you realize how good you feel without something you can't tolerate, you notice it more when that something makes you feel terrible. Though I don't know if your tolerance of it actually lessens once you rid it of your system.
ETA: I know I said "tolerance" a lot in my response but fructose malabsorption is, as the name suggests, a malabsorption issue. It's not a tolerance issue.
Fructose Malabsorption Disorder is the inability to absorb fructose and fructans. This condition is NOT characterized by the inability to "tolerate" fructose/fructans. Sufferers of Fructose Malabsorption have no difficulty tolerating fructose/fructans once they have been absorbed. However, inducing absorption is difficult or impossible for FructMal sufferers. The symptoms of the disease are the result of having unabsorbed fructose/fructans in the lower intestine.