The delivery platform represents a business relationship with a restaurant that doesn't exist, and uses it to pull value out of the services the restaurants offer. As a business you get to choose which other businesses you work with, and on what terms. In this case they haven't given the restaurant the opportunity to negotiate terms.

It's new ground sure, but I think it's pretty clear that the delivery platform is a service provider to the restaurant and as such the restaurant should have some negotiating power. What if they want a cut of the delivery fee, or guaranteed delivery windows for their customers? Probably wouldn't get it, but that's a negotiation they should be able to have.

Exploiting the customer my misrepresenting a restaurant as a partner when they are not.