Yes people can freely work for Lyft/Uber, but they can't work free. As in, the designation "independent contractor" means they should have a lot more freedom in how they conduct their personal business than they do at the moment.
Lyft/Uber keep their drivers on a leash while saying they're independent contractors. And that is exploitation.
I disagree with what you claim is a "leash". Have you ever driven for Uber? They have already made tweaks to give drivers more control over their fares and you always had control over when and where you work, along with which ride you accept.
More importantly these definitions are decades old and need updating for the modern era. The better solution would be to create a new classification between employee and freelance.
IIRC they only made these tweaks are being pressured by the government. They were perfectly happy breaking the law when it allowed them to grow quickly.
Lyft/Uber keep their drivers on a leash while saying they're independent contractors. And that is exploitation.