Usual disclaimer: this is not a rant, even if it may appear to be. I'm genuinely trying to understand if "there is a point", i.e. I may disagree with the community, but I may also be surprised and some member of the community might show me a different way to approach this.
Every setting has its own rules, every saga has its own pros and cons. While Harry Potter saga is really great for many reasons, internal consistency definitely isn't one of them: the author herself told time and again she genuinely doesn't care and "can't do math" and that this is fine for her and for most of her fans.
On a setting such as B5 or The Wheel of Time, or even Star Trek to some extent, while there are of specific instances of contradictions or mistakes made for the sake of entertainment, they still tend to be internally consistent and "make sense".
HP settings feels very "magical", in a traditional sense, and has a very strong and beautiful atmosphere, and this is a good thing. However, to accomplish this, it tramples any kind of stability to the setting, having plenty of contradictions, plot-holes, events, behaviour, plans that plainly just don't make any sense.
What I'm wondering is what's the point of trying to force some canon into that? If the answer is "the author just didn't care, the story is great nonetheless", what's the point of forging an answer anyway?
While there are some genuine and useful questions, most of them fit into this category instead, and I always feel quite awkward reading those.
If a single episode of Star Trek messes up an established fact, forcing some explanation might make a sense, since the setting as a whole is fine anyway... but here there's no consistency, there's no stability, so I kind of miss the point.
Hope this is clear and answerable.