I don't see it as fraud, because I don't think Uber's up-front pricing is them saying "this is the best deal for you, the customer", but rather an offer to the customer to buy a product at that price. They don't have any fiduciary duty to give the customer the "best rate."
This feels like the trend now of people realizing that bank tellers aren't actually fiduciaries and getting upset when they—i.e. customers—are sold financial products that might not be necessary or in their best interest. Matt Levine has a section on this[0] (skip to the section on "cross-selling") and why people are upset.
[0]: https://www.bloomberg.com/view/articles/2017-03-13/spoofing-...
This, to me, is the critical point from the rider side.
If drivers were ever told something along the lines of "We, Uber, take an x% cut of the fare" then I can see a court deciding that drivers were defrauded by Uber when they misrepresented what the user paid.
[0] Page 4, sub-section (16) of the court documents https://arstechnica.com/wp-content/uploads/2017/04/uberdrver...
In which case we'll see Uber, a company that seems set on self-destruction at this point, pay a moderate settlement that's unlikely to be material compared to their funding.
If I'm a trader in the highly volatile Celery Stalk market, and I sign a contract with a restaurant that I'll sell them celery at a 5% markup over what I'm paying, and I actually take 7%, that's not "free trade", it's fraud.
Now I don't know exactly what the details of Uber's pricing calculations are. So maybe it's not quite like celery skimming. But it sounds close enough, and is probably worth a law suit to find out.