This isn't mandating that uber has to hire these people, or that these people have to have jobs, it's that if Uber wants them to work an amount of hours equivalant to a full time emlpoyee then they need to not pretend that they're not full time employees.
The amount of time worked has nothing to do with it - contractors in other industries typically work long hours. The reasoning is that contractors should retain some level of independence, like choosing their rides, and setting their own prices, for example. Uber is micromanaging all driver's daily activities, which is antithesis of being independent contractor.