Unless you're able to show how Uber used violence or threats of violence to force drivers to work, it's not slavery.
Even if it was the only employer on the driver labour market, it still would not be slavery — but it's not even that. In almost any labour market that Uber operates in, it has competition.
Even if it was the only employer on the driver labour market, it still would not be slavery — but it's not even that. In almost any labour market that Uber operates in, it has competition.