Is milk a strange foreign substance foisted upon human kind by the dairy industry?  In its present form maybe?  But look at how it all evolved to this point.

Hit the reframe button.  Look at humans as symbiotic predators.

We turned from hunting ruminants to herding them.  Dogs turned into our partners in this herding, from their role as competitor predators.

Milk and blood were used as food obtained from the herding animals without killing them.  Laplanders use reindeer blood to make bread.  This efficiency allows a longer happier existence for all involved.

I'm not sure if this helps put dairying in persprective, but it is another way to look at it.  Reframing?

Insects are herders too.  

Are animals in a herd protected, but exploited by humans different animals from wild?  Symbiotically evolved with humans and dogs and cats.  

Cats protecting the whole arrangement from rodents.  Who co-evolved along with us all, as even bubonic plague and the fleas that carried it on the backs of the rats did too.

So we all are who we have become, together.  This whole agribizz factory treatment of our fellow creatures is not in the symbiotic mode.  It puts life out of balance.