There's a very simple reason developers are tending towards 'freemium' games: it makes more money (at least on ios). Let's be honest, as much as a developer may love making an app, if they are to invest the time and resources required to make it good, they need to get paid. So their options are ad supported, which often doesn't pay very well, a non-free app, which often won't get many downloads (unless you're a marketing guru), or IAP. IAP have the benefit of allowing a free app which gets lots of downloads, the possibility of ad generated revenue that can be disabled for a fee if the user wants, and the option for the USER to determine how much they want to give. It's (theoretically) win/win for developer and customer.
However, the kids apps are absolutely horrible. The apps themselves are usually quick hack jobs with some manipulative child psychology tricks in them. Adults often hate them and can't stand them, but the kids love them and beg and cry to get them. Then they dress up IAP in pretty buttons and what not so every thing the kid clicks on brings up a purchase window and the kid bugs the heck out of the parents to fix it... One slip on the parents part and they accidentally make a purchase.
Honestly, they need to go after the lecherous developers that make that trash, rather than ask apple to censor (yet more) apps from the app store.