I can not seem to wrap my head around the idea that donuts SHOULD be free. Of course it is nice when things are free and we get something for nothing but that isn't how life works and there is no reason it should be different for this game. The people that developed this game did not just plug a couple of pieces of data into a program and leave it to let it run. It takes a lot to develop a game and even more to maintain it, especially when it is as popular as this one, there is a lot of server maintance and continued develop to provide us with updates. Would you do your job for free? Of course not! So, why should they??? The game is advertised as Freemium, it is mostly free and can be played as such or you can purchase upgrades that are unnecessary for game play, however, do enhance gameplay.
Maybe instead of telling game developers to be ashamed of themselves, YOU should be ashamed of yourself for failing to teach your children that they need to earn things in life because most things, if any, are not free. They could do chores to earn an allowance and use that money to buy donuts for their game. While you're at it, explain to them that not everyone can afford donuts, just like in real life when not everyone can afford a Porche.