At this point, as in so many "manipulative Dumbledore" stories, I have to ask why Harry is returning to Hogwarts at all. Why doesn't he transfer someplace else? Or get some tutors to train him. He certainly knows he won't be learning the things he needs to know at Hogwarts, and will be actively impeded from doing so by the Headmaster.
Harry needs to learn more about the wizarding world's laws as well as defense. Dumbledore definetly would do all in his power to inhibit it. Finding private teachers would be more sensible. Plus, it would keep Dumbles from using obliviate on him or slipping some potions in his food.