Dairy is just bad in general, it's just that some people can tolerate it better than others. It's an inflammatory food.
BMJ study from 2014: https://www.bmj.com/content/349/bmj.g6015
"In subsamples of two additional cohorts, one in males and one in females, a positive association was seen between milk intake and both urine 8-iso-PGF2α (a biomarker of oxidative stress) and serum interleukin 6 (a main inflammatory biomarker)."
"High milk intake was associated with higher mortality in one cohort of women and in another cohort of men, and with higher fracture incidence in women."
8-iso-PGF2α is produced by inflammatory cells (mast cells, etc). You do not need to have clinically significant allergy or sensitivity to suffer from chronic inflammation, which can be silent.
Dairy is inflammatory: https://www.arthritis.org/health-wellness/healthy-living/nut...
As you can see, the Arthritis Foundation does not give blanket recommendation to eat diary "because cal/vitD". Instead they urge caution and even try diary elimination.
Another study, 2015: https://pubmed.ncbi.nlm.nih.gov/26674761/ "Directly Associated with Dairy Food Consumption and Low-Grade Inflammation in a German Adult Population"
Another one, 1994. “Consumption of dairy products, particularly at age 20 years, was associated with an increased risk of hip fracture in old age. (“Case-Control Study of Risk Factors for Hip Fractures in the Elderly”. American Journal of Epidemiology. Vol. 139, No. 5, 1994).
One more, from 1997. “Data does not support the hypothesis that higher consumption of milk or other food sources of calcium by adult women protects against hip or forearm fractures.” (Source: Feskanich D, Willett WC, Stampfer MJ, Colditz GA. Milk, dietary calcium, and bone fractures in women: a 12-year prospective study. American Journal of Public Health. 1997).
12 year long Harvard Nurses’ Health Study found that those who consumed the most calcium from dairy foods broke more bones than those who rarely drank milk. This is a broad study based on 77,761 women aged between 34 and 59 years of age.
25 years of results that point to no benefits at best, and corroborate association of diary intake and chronic inflammation at worst. Got milk?