What does that have to do with employment status? Does the Dutch Commercial Law state that the employees should only work on firm-appointed hours? The hours worked are already logged, the only new responsibilities fall on Uber except for filling a few documents for employment.
They can still offer flexibility. No one was really, really autonomous, autonomous, though.
Are the drivers you talk to actually friends of yours? Are they driving to make a living? Are they stuck driving due to poor child care choices? Are they on the clock and hesitant to dismiss the company they work for?
Have you asked them if they'd rather the company process the taxes? Do they have difficulty doing so? Have any of them found themselves in a hole because of the 'contractor' system?
I'll add that this isn't like a normal contract job: Uber needs drivers. Without drivers, they wouldn't have a business. And they need them constantly - not in the way that a firm needs temporary help to upgrade things.
What is it in us that can’t let people have what they value, just because it is different than what we value?