The problem is the ordering platforms enabling this integration without restaurant consent. (Or, perhaps worse, offering orders without restaurant consent?)
Google just provides an API that allows restaurant ordering from Maps, Search etc. It connects to the ordering platforms (e.g., DoorDash) [1]. The ordering platforms integrate with this API by uploading data feeds and implementing a server with specific interface. [2]
I don't think Google even takes a cut!
I worked on an integration to a similar API, "Reserve with Google" [3]. With that one, at least, it can be enabled/disabled at the restaurant level. I assume that "Order with Google" is similar.
[1] https://developers.google.com/actions/food-ordering
[2] https://developers.google.com/actions/food-ordering/guides/b...