Anytime you have a situation in which a "cult" based mentality exists, be it a religion or trade union (remember that socialist union in Germany a few years back?) fanaticism can ruin the original intent... this is especially so when human ego and the lure of power (influence) over others starts oozing into things. History shows us all kinds of examples where this has been the cause of horrid acts of inhumanity or outrageous disrespect (such as the destruction of the Buddhas in Afghanistan a couple of years ago).
The UTNE Reader had an article in it some years ago (I'd have to say it was at least 12 or so years now) in which a magician took a tour through the Pacific Islands with the intent of doing street magic as a way to support himself during his travels, etc. He however came into a situation that was totally unexpected; literal threats on his life made by the local Shaman because the magic he was doing on the streets (Sponge Balls, Cups & Balls, etc.) was superior to what the Shaman could demonstrate; the Shaman seeing his actions as a challenge for territory... a very common thing that's been practiced for mellennia in these "remote" areas of the planet.
This magic student managed to turn these circumstances into a serious learning experience as well as being an important source when it comes to how a large part of world culture -- those that live outside the Western influence as well as those surviving in the more rural areas of society -- hold to a belief and perspective towards "magic" most of us can't comprehend. But when we step back and consider this, we can see why situations such as this article speak of, happens. But at the same time, we owe it to both, ourselves and the idea behind what a Sorcerer or "Wizard" is and is not; something few ever consider.
For most of us such entities are persons that can wave a hand and make unusual things happen or cause demons to appear, etc. These are the conjurers of fantasy not what they were in reality. But then we could look at a character like Merlin and when weighed against "reality" see just how his "magic" was little other than an understanding of engineering (physics) principles and psychology. He was very matter of fact about things and yet most everything he is said to have accomplished hosts a rather simple explanation by today's standards... but then, that's the rub, isn't it?
As I've pointed out before, knowing the secret behind the magician's tricks does not make the manifestation any less magical or "fake" as some would say. This is the case of Wizardry; we might have learned some of their secrets but that does not neuter how they were perceived and why... nor the sense of prowess they held as the end result of this perception. What we are missing however, especially when it comes to someone like Merlin who may very well have existed (just not as we've been lead to believe via the novels) are the other actions that create enchantment and thus, legend; his manner of charm or charisma, grace, general wisdom and manner of counsel. These are the things that establish someone as a "Wise-ard" (as it was seen in the old tongue); a kind of shaman who's had a bit more formal indoctrination and training. In the case of Merlin we are looking at the Druidic traditions and the fact that the name was actually a title, not a single person. This is probably why we can find a Merlin (akin to a high Bishop to a given region) that seems younger in one era than the Merlin of previous generations (one of Merlin's more noted traits was to age backwards, from old to young).
Understanding these things and the other odds & ends that sustain the points I'm striving to emphasize here, allows us to better accept the "Magick" offered up by such entities past and present; seeing it as "real" but only due to perspective.