Best to remember that certain sensitivities, like lactose intolerance, are actually the rule rather than the exception. Lactose tolerance is only the majority in certain populations of European or Middle Eastern origin. A bunch of them are also mostly harmless and just cause indigestion rather than anything serious. I am lactose intolerant and eating cheese just means I’ll be gassy and spend more time on the toilet later, so long as I’m not eating to excess. Since they don’t actually kill you most of the time, they get selected out at a very slow rate.