Sure, Uber drivers aren't forced to work at Uber specifically, but everyone is obligated to work in a capitalist society if they want to survive, so it is important that employers in general are bound by laws that protect workers.

In this case, California created new laws in response to employee abuses at Uber and Lyft.

This notion that Uber and Lyft drivers can afford to quit and find a new career is infantile. The real world does not work that way, and people who labor for low wages should be protected from abuse.