Is it actually illegal for a driver to deny a passenger with a service animal or based on religion, race, or gender?

Yes, I know I can be deactivated, but is it actually illegal?  Can I be sued?

Remember, the drivers are independent contractors driving our own private cars. I understand that I can cancel rides for pretty much any reason out there. 

(I was discussing this on this thread, but I decided to create Guru Question: https://ride.guru/lounge/p/can-uber-and-lyft-drivers-refuse-a-passenger-for-any-reason#comment-14739)