There's an important difference in both cases compared to what Uber is doing and that is that Uber is in complete control of whether you will get work.
Moreover, they have much more opportunity to do it since a strip club and barber salon have a lot fewer rented spots (ones/tens vs hundreds/thousands) and there is more ways Uber can be sneaky about it. (Oops sorry it took us 10 minutes to find you a passenger)
OH there's also the fact that Uber has the ability to arbitrage. Since the drivers who payed in are more costly to Uber to send passengers to than the drivers who didn't. Unlike the other industries you mentioned where presumably everyone has to pay in.