> no dairy

They couldn't find one mammal from which to obtain milk? It's a pretty obvious thing to try, for obvious reasons.

The vast majority of the human population is lactose intolerant, both historically and today. Genetically intolerant populations in South and Central Asia have microbiotic help with their dairy-heavy diets, but for people who didn't spend thousands of years developing a culture around it, dairy is just a quick road to an upset stomach and/or food poisoning.