Does it really make sense economically for Uber to get 100% of the cost of a ride this way but having to spend money to buy main, maintain and insure cars?
If you hypothesize that robot drivers can really do the job sufficiently well, the conclusion is an extremely strong and obvious yes. Taxis, limo services, etc are already viable business models even when you have all those same expenses plus a driver to pay. Remove the driver expense and it only gets more viable.
Or is this another sign of a company that doesn't know what it is doing, perhaps most recently suggested by the recent charges of sexism and sexual harassment?
It's possible they don't know what they're doing, but this certainly isn't a sign. It all comes down to whether or not you think robots perform as well as humans, and this story merely works from the conclusion that they can; it doesn't show any strengths or weaknesses of the premise itself.