Honestly I just feel like you may have wielded judgement too hastily at the expense of your sense of wonder and shared joy in someone exploring territory that is well trodden only to relatively few. Very few people have a solid grasp of musical theory. For most people, scaling what may to you be barely the foothills of knowledge is a great and challenging experience, and I think it should be celebrated.
And sure, perhaps you and I can easily distinguish the subtle difference between 'Musicians always use chords' (obviously wrong) and 'Musicians always work, individually or together, within a key, which is an abstracted but well-defined set of tones that can be combined in time series or simultaneously to produce an inexplicably pleasant experience in the listener, by some neurological magic that has never been adequately explained' (non-obviously correct) but y'know what, I actually am willing to let little gems like that slide because they're adequate approximations of the truth that allow good folks to proceed on a journey that may one day lead them to, just maybe, have the arrogance required to belittle the uninitiated.
For me, the issue was that the writing style, like most articles written by programmers, passed off every thing as fact. Things like "they have the same chord progression" in section 2.a is patently false. This kind of writing is misleading to others, especially newcomers (blind leading the blind)
I do agree though, that to do somethimg, learn something, have something almost correct is better than having learned and done nothing, but as Bill Evans points out in the youtube video about the learning process, it's much better to start with something simple, concrete, and which you know as true then build from there, than start approximating (incorrectly) lots of things at once. So it's a case by case basis, but it's not merely gratuitous arrogance that motivates people to call other people out on false statements.
> Very few people have a solid grasp of musical theory.
This is just like saying that very few people in the world have a solid grasp of computer programming... Do you know that there are hundreds of university departments in the world where the only thing people do is, wait for it... having a solid grasp of musical theory!?
Not everyone if the world is trying to create a computer model of music. The minimum a person with this interest can do is to contact a specialist in music theory (of whom there are thousands as I mentioned).
And sure, perhaps you and I can easily distinguish the subtle difference between 'Musicians always use chords' (obviously wrong) and 'Musicians always work, individually or together, within a key, which is an abstracted but well-defined set of tones that can be combined in time series or simultaneously to produce an inexplicably pleasant experience in the listener, by some neurological magic that has never been adequately explained' (non-obviously correct) but y'know what, I actually am willing to let little gems like that slide because they're adequate approximations of the truth that allow good folks to proceed on a journey that may one day lead them to, just maybe, have the arrogance required to belittle the uninitiated.