I don’t know the ins and outs of the ADA, but I disagree with your analogy. What Starbucks is doing is akin to Walmart charging a different price for milk and oat milk, which I don’t think anyone would say is not allowed. It’s not like there’s a sheet of lactose you have to walk through to get into a Starbucks or anything, there’s just things on the menu that people with some food allergies can’t order.