This is a classic case of defending the status quo. Here’s a simple way to tell if that’s what you’re doing: imagine for a second that milk was a new product, designed to take on existing beverages made from hemp, oats or nuts. Defending oat milk against the incursion of cow milk is pretty easy.
The author could point out the often horrific conditions used to create cow milk. “Wait, you’re going to do what to that cow?” They could write about the biological difficulty many people have drinking it. Or they could focus on the significant environmental impact, not to mention how easily it spoils, etc.
Or imagine that solar power was everywhere, and someone invented kerosene, gasoline or whale oil.