It should be illegal because these services market a subscription to you claiming the benefit of zero fees and free delivery, which is a lie. You are being secretly charged through a higher menu price, none of which is shown to you as a customer.
I can't count how many friends I have had to explain this to who don't understand they are paying 20-30% more even after getting "free delivery" than if they just ordered directly through the restaurant.
Also, Doordash does not have "zero fees" for orders when you pay for DashPass, they have "reduced" fees. I do absolutely hate the practice of "Taxes & Fees" being a line item and only when you click into it do you see that the taxes are minimal and most of that is the platform fees.
I'm not sure how UberEats/etc handle it but it's absolutely crazy how much of a markup there is to order through Doordash vs going to pick it up when you factor in Restaurant Upcharge + Doordash Fees + Tip. It's easy to have an $8 item suddenly cost $20 or more total out-of-pocket when all is said and done.
I can't count how many friends I have had to explain this to who don't understand they are paying 20-30% more even after getting "free delivery" than if they just ordered directly through the restaurant.