I don’t think I or any rational adult of sound mind and health would look at someone drinking a carton of milk and have anything close to a thought at all, much less a thought of ridicule or judgement. I am not getting or connecting with the persecution complex in this post.
The reason you don’t see people drinking milk as commonly as other drinks is that lactose intolerance is a huge thing, and even if you don’t have a genetic predisposition to lactose problems, as you get older it gets harder and harder to digest. This is why milk is often associated with kids, it’s good for growing bodies but not so much for someone who’s already an adult.
Also, it’s not that refreshing. The fat content makes it feel less hydrating than water or fat-free liquids of any kind.