Let's put this part to test. I hereby claim that I can teach you how to transmute lead to gold by waving your hands. I'll teach you the exact movements. Then someone can hand you a chunk of lead, you'll wave your hands and observe the results of the process I taught you. It's your responsibility not to expect explanations of observed inconsistencies -- between gold and what you have in your hands -- to be spoon-fed to you.
If we really did the above exercise, your conclusion would be that my claim is false. We could go even further than that. I could claim circumstances were not right. I could accuse you on basing your conclusion on anecdotal information. But somehow I doubt I could convince you or anyone else that I'm not a charlatan.
Ah, but I can't produce "authoritative texts (original works)" that reasonably and convincingly explain "the underlying principles" of transmuting lead to gold through hand-waving, could I?
Okay, no problem, let's change the example to "getting laid through neuro-linguistic programming". There are people who believe in that pseudo-scientific bullshit even today, so long after it's been proven to be total crap.
Do you honestly think that you could apply your argument about "not expecting to be spoon-fed explanations of observed inconsistencies" to NLP without being laughed at? I'll assume you don't and ask you why the heck you tried to pull the same argument when it comes to "Agile"?