The difference : try to find an Uber driver who accepts to drive 200 miles for $10.
Uber is not at all like ridesharing. With ridesharing, several people who go to the same place share the same car. It is good as it decrease traffic congestion, pollution, etc... With Uber, it is the same as when you are driving by yourself regarding pollution and congestion, the difference is that you are not the driver, i.e. it is a taxi service.
Price is telling too. With ridesharing service, the driver usually get barely enough to cover the car running costs but it is fine : driver get to drive basically for nearly free and passengers get a cheap ride. With Uber passengers pay for the driver's time, like a taxi.
And now, why regulate Uber drivers more than ridesharing drivers ? A reason I can think of is that because of the finencial insensitive, Uber drivers will spend more time than normal on the road, increasing the risks. Rideshaing drivers would be better off not driving at all, they simply take passengers to lower the burden for the trips they would have done anyways.
If you want to compare with sex, I'm not against paid sex. However it is normal to have laws targeting prostitution because of the increased risks (STD, ...), either by regulating it or banning it altoghether. (putting aside questions about morality and crimmnality).