At a tech conference on November 2, Uber (UBER  ) Whistleblower Mark McGann said that, while Uber seems to be making an effort to improve its workplace culture, the company's business model is still "absolutely" unsustainable.

In July, the former top lobbyist for Uber, McGann, leaked a trove of more than 124,000 Uber files revealing how the ridesharing company had evaded regulations and law enforcement and secretly lobbied politicians, Russian oligarchs, and media companies. McGann says he decided to leak the communications because he felt Uber was knowingly misleading people about driver benefits and willfully ignoring laws.

Since then, the company has "done a lot of good things, but they have so, so far to go," according to McGann.

"My message to Uber is: 'you've done well, (but) you can do it so much better (because) the current model is absolutely not sustainable,'" McGann said at the Web Summit in Lisbon.

In particular, McGann pointed to the ridesharing company's reliance on independent contractors and the labor market's trend towards self-employment and employment flexibility. However, he says that positive perception of independent contract work isn't accurate.

"Uber is pumping tens of millions of dollars in Europe, United States, other parts of the world fighting legislation," McGann said, referring to attempts by drivers to sue Uber for even "a basic minimum of social protection such as sick pay."

For its part, Uber says, "We have not and will not make excuses for past behaviour that is clearly not in line with our present values."

When asked to respond to McGann's statements, the company told Reuters reporters to refer to a New York Times op-ed written by Uber CEO Dara Khosrowshahi in 2020. In the piece, the tech CEO called the company's employment system "outdated and unfair."

Still, Khosrowshahi wrote in support of independent contract work, arguing that becoming employees would restrict driver flexibility and increase ride prices. Rather than changing driver classification, Khosrowshahi said that lawmakers should create new protections for gig workers.

"I'm proposing that gig economy companies be required to establish benefits funds which give workers cash that they can use for the benefits they want, like health insurance or paid time off," Uber's CEO wrote.