Something else to consider is that new magic is may be dangerous because it's not yet been properly tested, and would any of you seriously trust much of the Wizarding World with something that hasn't been properly idiot proofed? It's quite possible that atleast part of the magic classified as Dark is classified as such to keep it out of the hands of the public until it's been properly studied, after which they declassify as Dark Magic.
And this would actually be a sane and reasonable line of thinking, if not necessarily wise and well thought out.
And this would actually be a sane and reasonable line of thinking, if not necessarily wise and well thought out.