Drinking Milk into Adulthood

So, this topic has been discussed (at annoying length) at my work. I was thinking about it this morning and thought I'd get some additional opinions on it.

Person A says that milk is produced by a mother to feed its young. Person A finds it gross to drink a glass of milk because they believe it's unnatural and unnecessary. Specifically, person A thinks that because it's not very common in nature to see animals drink the milk of another animal that it makes drinking cows milk gross to them. (note person A does not mind milk as an ingredient in things or cheese) Person A also likes to cite a high percentage of people develop lactose intolerance as they age.

Person B says that, because we're a more advanced species, we've learned to harvest things other animals wouldn't be able to. That other animals probably would if it was as easily accessible as it is for us. That's why if you gave a cat a bowl of milk, it would drink it. Person B thinks if you're willing to eat the meat from an animal there should be no issue drinking its milk. Person B also states that if you're going to use the unnatural excuse, to do it across the board and not just use is as an excuse not to drink milk.

Do you agree with either of these people? Additional thoughts? I understand both sides of their agreements and would like to hear any additional opinions or facts you have.

**EDIT: for the record neither person is being judgemental or trying to tell others what to do. Just expressing how they feel about drinking cows' milk.**