Having trapped themselves in a nonsensical situation where the EU dairy industry not only enjoys massive subsidies (not just for production but for export too) but is classified as a separate food group on official nutrition guidelines health professionals seem unwilling to believe research that milk is perhaps not the best biochemically available nutritional source of calcium.
The anomaly that the biggest consumers of dairy in the world are also the biggest sufferers of osteoporosis seems to escape them as does the white elephant in the room that so much of the world gets along just fine without dairy. Those countries that do start consuming dairy then begin to follow the western world's path of avoidable chonic disease.
Calcium is an important mineral but is found in abundance in vegetables and it's absorption is greatly enhanced by vitamin c also found in vegetables.
There is an interesting study on vegan nuns in Vietnam that suggests that although calcium intake is lower than omnivores their bone density is equal.(citation needed)
Some health professionals suggest that the acidity of a non vegan diet leaves a net deficit (more in but more out too) as calcium is used to buffer elements of a non vegan diet (citation needed)