Those guys are no contractors. There are laws with different treatment based on telling signs that a worker is an employee. I can't tell about the USA, but around here you're an employee when you work for one employer that decides the hours and other details, and provides the basic means for the job (the app in this case).
basic means/tools -> car
you set your time and drive whenever you please or not at all
so in conclusion even by your test you are not employee
Pretty sure that Uber/Lyft drivers set their own hours and many of them use many different ride sharing apps.
The guys that deliver food have been declared covert employees recently here in lower jurisdiction. Not sure about taxi apps, there must exist a loophole at least to start. The question is you are very dependent of some party.
The are still subject to work law.
If the work law in US does not protect them, that is another matter.