Snapedom

Not all dark magic IS illegal. See my point about Borgin and Burkes operating legally. Also, if dark magic is defined by its ability to cause harm: 1) why aren't far more things explicitly called out as dark magic, both in the books and/or in your theory, and 2) the cursed necklace that Draco buys would then be dark, but it is apparently quite legal to buy it, sell it and possess it, so again, not all dark magic even under your definition would be illegal according to canon. So no, your criteria switching does not hold up. Dark does not equal illegal in canon even applying your theory of dark magic to it.

And I know you were answering oryx's question; I assumed you were not averse to other people replying however, and when I ask questions I am interested in actually hearing the other person's response to them, which is why I asked. You don't have to answer but I'm still curious what you make of any of my points/questions.

Regarding practicality: we seem to be talking at cross purposes. You now claim you are interested in 'practicality' in the use of spell casting whereas the discussion to me had seemed to be about whether or not your theory of dark magic is supported as 'the right' theory in canon. Maybe you aren't interested in having that discussion and I and oryx just aren't getting it?