Missing the forest for the trees there Tobberoth. Harry Potter is one tree. If that's all a person read, then they don't really care about learning Japanese. It's 450 pages out of the 100,000+ pages of material one should read over time.
It's literary equivalent of guys moaning Heisig taught Gall Bladder way near the beginning of 2000 kanji instead of the end. It's a moot point. If the Gall Bladder kanji were all one learned, yeah, that'd be pretty stupid. Don't bitch just because I tossed that kanji on top of the rest I'm going to learn.
Now, had you extended effort early on talking about that other book ドロップ, you would have others not only agreeing with you, but maybe want to try out the book. Instead, we have 10 posts talking about the book you don't want people to think about. By insulting Harry Potter, you bring out defense actions from others to justify their reasons for reading. If you offered a suggestion of something else, you instead get inquiries.
It's the whole attracting getting more flies with honey instead of vinegar (or a sharp downward slap of the hand).
It's literary equivalent of guys moaning Heisig taught Gall Bladder way near the beginning of 2000 kanji instead of the end. It's a moot point. If the Gall Bladder kanji were all one learned, yeah, that'd be pretty stupid. Don't bitch just because I tossed that kanji on top of the rest I'm going to learn.
Now, had you extended effort early on talking about that other book ドロップ, you would have others not only agreeing with you, but maybe want to try out the book. Instead, we have 10 posts talking about the book you don't want people to think about. By insulting Harry Potter, you bring out defense actions from others to justify their reasons for reading. If you offered a suggestion of something else, you instead get inquiries.
It's the whole attracting getting more flies with honey instead of vinegar (or a sharp downward slap of the hand).

I don't see how it is useless at all.