Don't be dismissive of audio engineers and mixers making records. I don't think you realize how much care and consideration goes into crafting an album. These choices are far from arbitrary for those who are working at the top of their craft.
Additionally, don't make the mistake of conflating people who are "hi-fi" enthusiasts with the people actually making the records. They are not always aligned in their goals.
You also seem to have the mistaken idea that mastering engineers are trying to impose their taste onto a record. You know which mastering engineers try to shoehorn their taste into a record? The ones who don't get hired a second time.
I am a mastering engineer. By the time that a record reaches our studio the creative decisions have already been made by the artist, the producer, and the mixer. Our goal at this stage is to function as midwife to the artist and present their music in the best possible light, which sometimes means doing as little as possible, so as not the get in the way of what's been delivered to us. Our role is to hear the record as objectively as possible and then give it a final level of polish/balance so that the artist's intentions shine through and translate on as many different playback situations as possible.
Finally, if a guitarist's amp is putting out too much 6kHz at a rock show, then it is the live sound engineer's responsibility to fix it, either through EQ or through communicating with the guitarist to adjust their amp settings.
For live music, there is no reference for correctness. The raw thing is so loud, it hurts. Nobody is engineering it for listening at moderate volume in an ideal listening space!
Now speaking of recorded music, even though there is a "correct" approach to reproducing it so that you hear more or less what the recording guys (I don't want to use the term "engineer" because often they are not) intended.
However, what those guys intended is often arbitrary. They took captures from some sources and tweaked them. The whole hi fi paradigm is predicated on the idea that the recording/mastering guys are high priests who get to exercise their taste, and the lowly consumer must obligingly reproduce what they put out.
This isn't so at a concert. If it sounds to me like some guitar dickhead's amp stack is putting out too much crap above 6 kHz (because he's standing out of its way, hearing it from the side or whatever), and my foam plugs make it smooth like it should, that makes me the "engineer" of my own experience of the event.