... because regulation makes them safe?
Seems the reality is, noone knows, because noone collects statistics that would tell us.
e.g. http://www.independent.co.uk/news/uk/crime/taxi-drivers-uber-charged-violent-sexual-offences-london-a6988286.html (UK) or https://www.theatlantic.com/technology/archive/2015/03/are-taxis-safer-than-uber/386207/ (US).
All we know is that Uber has a reputation problem. I could propose two hypotheses, but offer no comment on which is closer to reality:
(a) The reputation problem is fully deserved.
(b) The reputation problem arises from an entire industry having a strong vested interest in stopping the rise of Uber.