The real crime is that Valve requires price parity when you independently (no Steam keys) sell your game on a different store, as well as the Steam store. ("Most Favored Nation" clause.) It means that developers are allowed to pocket the profits if a game is sold on a store that has a lower percentage cut, but they aren't allowed to share the lower cost with the customer, because that could encourage people to not use the Steam Store when buying games.
I've looked through court documents for this. They're sneaky about it, but they implicitly threaten you with your game's sales being crippled by being taken out of their recommendation algorithm. With Steam being the biggest store, that's a death sentence for most indie developers.