"Uber screened and trained its drivers, and drivers could get deactivated by Uber for having their rating dip below what local managers set as a cut-off, for not accepting a certain percentage of trip requests, or for customer complaints.
You don't defraud eBay/customers by saying you have a good when you don't actually have it, and you don't defraud Uber/customers by saying you are available to drive when you actually aren't.
You can choose when to offer an item for sale, and when you choose to be available to give rides for Uber.
Not to be pedantic, but do you have a source handy that indicates this? I would just like to have one for reference.