It is also one of the few non-sugary examples of a kids drink so I'm quite keen on it.
I liked it when I was young.
You haven't looked very hard, then. My 2 year old loves milk and requests it so much that we're actively trying to get her to drink less (and more water). All my friends who have kids in the same rough age bracket report that their kids ask for milk, too.
I have been extremely lactose intolerant since childhood, so those forced milk-drinking episodes were traumatic.
These days I get my calcium from dark leafy greens, sardines, and tofu. I get my vitamin D from sunlight and an easily absorbable vitamin supplement.
I think this has more to do with 'common knowledge' of what's healthy.
It's also certainly better to have your kid drinking milk, over sugar waters, like sodas, most fruit juices...
When our daughter was born, we spoke to a lactation consultant who explained how infants wean away from breast milk naturally. She explained that it's not cow's milk that has a similar taste to breast milk, but it's bananas.
We also get bombarded with ads "If kids need to get sufficient calcium and Vitamin D, they need to drink cow's milk". I'm not sure how valid this argument this is.