Some people have moral frameworks that always make seeking profits immoral. I'm not sure if that's what OP is saying, or merely that showing the driver and the passenger different rates and subtracting the difference (this is an approximation, not exactly what the post said) is shady and bad.
From previous HN discussions my impression is that the primary issue is with this charge being implicit. Uber already takes its money from drivers, and both drivers and users are participating in the program based on the assumption that what user is charged = what driver gets, minus Uber fee. But then it turns out that what user is charged more than Uber tells the driver (and from what it subtracts its fee), while the company also pockets the difference. This feels wrong.
