They generally argue forced tipping is a poor system.
I think they say 16% of Uber rides leave a tip. But that is about what the company wanted to see when they allowed tipping on the app. They other interesting thing they said was that tipping didn’t really increase Uber diver income on average even though 100% of the tip goes to the driver. On Uber men tip more than women.
In general I think tipping is dumb. It’s racist, sexist and tipping practices make no sense.