A substantial percentage of the population (10% to 15%) has IBS-like symptoms, and would be sensitive to even small amounts of polyols (another name for sugar alcohols).
Hence why they are excluded in a low-FODMAP diet (the P stands for polyols).
Wow, WP has 10-15 in the developed world and 15-45% globally. I never knew it was such a widespread thing. Crazy, yeah, that would certainly change it for them.