The fundamentalism (at least on my part, I hope) is against those who "proclaim that their way of listening to music is the purest" as you put it. Even though I don't have a vinyl setup and haven't for years, I don't resent people who listen primarily to vinyl. I have problems with the evangelists who either don't understand, or lie - those who say that vinyl not only is purer, but is the only way to have any kind of relationship to the music.
The point where I get angry is when someone walks into a hi fi store or seeks advice about their first system and is immediately told they have to have vinyl to appreciate music, because these days it is unnecessarily expensive, it is unreasonably awkward ("quite a bit of fiddling") and as you say, it is objectively inferior. I want people to listen to music at decent fidelity. If for them vinyl is part of the answer, and that can be for any of several reasons, they can discover it after they start by owning something great - a reasonably priced system that is easier to use, objectively better, and makes much of the world's music easily available to them at best quality.
Back in the 1980s. the goal of the hifi industry was to have higher fidelity than vinyl - we used to dream of having access to a copy at the standard of the master recording. So, now we can, easily, and guess what? The supposed experts (and often the very same pundits as back then!) are queuing up to tell us that that is wrong, and we should not only use vinyl, but indeed pulling away from high fidelity with recommendations and awards for equipment that would not have passed QA at the Leak factory in the 1950s.
Much of your post I can happily agree with. I had high fidelity from my turntables and vinyl and had it for the best part of 40 years. I disagree with your last four words, and that is based on both the objective numbers and my personal experience. I listen a lot to supposedly simple music - classical guitar, lute, solo harpsichord and piano - and my experience is that detail in such recordings is obscured when listened to intently on LP. The first three of those need very little processing to put onto LP and should be the easiest to reproduce that way. Maybe that's nitpicking, but that's my viewpoint.
There's one more thing. As the loudness wars have receded, there's a different attitude in the industry. Still, though, they continue to serve up digital recordings aimed at the lowest common denominator playback, and excuse themselves from any responsibility by saying that audiophiles only want vinyl. That works against not only self proclaimed "audiophiles" but anyone else who may have bought equipment - maybe modest but better headphones, for example - to get improved digital sound.
It's not high fidelity LP playback that is the problem - it's that big expensive lie that hurts us all, and it's the big expensive lie that brings out the vitriol.