Those firms claim that their drivers are subcontractors, not employees. While there has been debate about that, and a few states have taken steps to ensure those drivers are classified as employees, right now in most states, including Idaho, the drivers are still treated as subcontractors. Subcontractors don't benefit from all the rights and protections that employees have. That's one of the major reasons those companies choose to treat you as a subcontractor. They can refuse to hire you or terminate your relationship with the company for pretty much any reason other than discrimination based on race, sex, color, national origin, religion, age (over 40), mental or physical disability under Idaho law. Federal law covers only race, color, religion, or national origin for places of public accommodation, and it's unclear whether these app based services fit a place of public accommodation. Since your terminations/refusal to be hired were not based on any of those criteria, they weren't illegal.