"So that basically means if the Kindle app wants to let you buy books from Amazon, it has to go through the Amazon website and it has to allow you to purchase b

"So that basically means if the Kindle app wants to let you buy books from Amazon, it has to go through the Amazon website and it has to allow you to purchase books from Apple? How does that make any sense?" It doesn't at all and I totally agree with you on that. I was just making it clear what Apple actually said because everyone seems to be latched onto the "Apple won't let you access your own content if you didn't buy it from them" fallacy. Obviously Apple wants in on the purchasing action, and by forcing both actions to be available (staying in-app to purchase or being sent to a web browser) they are hoping at least some people find in-app purchasing easier/smoother and use it instead.