The author is implying that if Uber drivers were employees, then they'd behave better and the experience would be more consistent.
That's just bullshit. There's nothing special about the employee status, the only difference being that the employment law applies. But there's always a contract in place when hiring contractors and if anything Uber can demand much more from contractors than they can from employees. And if you want proof to the contrary, you only need to look at taxi drivers, many of which are employees of bigger taxi companies.
Then there's also the issue that the article is comparing cab drivers with highly skilled professionals, the kind that end up working in startups.