In-app purchases are not inherently problematic, it's when they are used as a core mechanism to play the game that they become a problem. I have no problem with in-app purchases to make things easier, or let people skip levels when it's not a direct competition between players. That might even induce some developers to actually put some challenge into the game. The problem is when it's not just challenging, but nearly (or actually!) impossible without the in-app purchases. Then we're talking about a bait-and-switch, and that infuriates me as well.