I think it's perfectly reasonable to blame/be upset with both the delivery operator (for infringing upon the restaurant's trademark by causing confusion as to the source of goods/services), and the e-commerce platform for knowingly facilitating/allowing the trademark infringement to occur on its platform. This is called 'secondary' or 'contributory' infringement in legal jargon.
If it's the delivery operator's business model to buy ads to get a cut of an order, then, we should be upset with the delivery operator.
(edit: removed off topic and specific business)