What Uber is being criticized for in this instance is an increased profit during a potential disaster via their surge pricing. They have defended this pricing by saying that it serves to get more drivers out during times of heavy need. However, if that truly was the case, there’d be no need for them to take the correspondingly larger cut that comes with that pricing, and they’d funnel more money to the ones doing the actual work — the drivers.
You’re right — people don’t have to take Uber. But that doesn’t mean they don’t have a right to complain about a business practice they see as shady. Uber is entitled to take whatever cut they choose. And customers are entitled to vote with their wallet… and their mouth.