The majority of Americans that drink espresso drink it with milk.

Depends on where you live.

Have you lost your mind 8)

Espresso is so named because you "express" the brew from the beans and you do that with water because water is pretty neutral in flavour, is not poisonous and has quite a few other properties that we have evolved to exploit or live with.

Milk is a weird liquid associated with mammals nursing infants. We humans have evolved to be somewhat lactose tolerant post infancy which is rare in animalia (1)

Given that we are using the Italian word - espresso - then let's use their definition. If you add milk then you have a latte or a cappuccino or an americano con latte, a flat white or whatever.

Real weirdos try to milk oats. I've tried but I can't find their teats.

1. https://en.wikipedia.org/wiki/Lactase_persistence