The value isn't to the milk cartel, it's to alternative milk producers. Imagine an ad for a new oat milk with "milk.com" as the domain. It's got a ton of media value.
In some countries you're not allowed to call them milk, for example, in the UK a judge ruled that they must be called something like "oat drink" instead.
Which actually makes sense. If it's not coming from a mammal's mammary glands, it's not milk!
Calling it milk IS deceptive marketing.
they'd not be calling their product milk, it would just be the name of their domain. you don't buy amazons at amazon.com