If Humans are Supposed to Eat Meat why are They So Good at Digesting Starch

Recently I was challenged with this question. A listener stated,

"Humans have a lot of amylase enzymes which means that we are heavy starch eaters."

It was stated like a silver bullet objection to my contention that humans are biologically designed to primarily consume animal protein and fat. Thing is where would man prior to broad scale agriculture obtain his calories from in the form of starch on an ongoing basis?

Specifically in the 80-90% of the land mass outside of the tropics and sub tropics. There is no answer to this question other than he could not have. Yet the listener is right, we do have an ability to digest starch, which is well, sugar. So why?

As you will hear today, the answer requires us to look at how humans lived for 99% of our history on the planet prior to the advent of row cropping.