Well, they hide the fact that the food prices are marked up for one thing. Even if you pick up yourself, menu prices in DoorDash are at least 20% above the restaurant’s posted prices. That undisclosed upcharge comes on top of the delivery fees and service charges they do disclose — but only after you have made your order.
I don’t see a problem with that. They show a price for a product. They have no responsibility to inform you that a lower price for the same product is available elsewhere.