The very term "hi-fi" means high fidelilty, i.e. your system should provide an accurate reproduction of the source signal with high levels of detail and resolution and minimal colouration and distortion. Your ears and the subjective measurement system between them (both of which become less reliable with age, however gifted you are in musical appreciation) can't tell you that
For most ordinary people hi-fi means a music reproduction system. For us it is not an absolute but relative description, otherwise we could call our systems “highest” fidelity. High just means something with greater fidelity than something lower. Fidelity isn’t defined but assumed to be relative to the incoming signal. Personally I think of hi-fi as something which reproduces the original sound, as best as possible, in a manner that fools me into thinking I am hearing the original sound.
Sadly, for it would be very convenient as a means to choosing our equipment, “best measuring” does not necessarily translate to into something that recreates an illusion of the original sound. I am typing this in the gloom trying out an ECM jazz recording. The trumpeter sounds as if he is in front of me, real and in his own space. The drums are so visceral that I can imagine someone tapping real objects in my room. That for me is hifi which employs speakers that have been variously described as making use of the room to add (bad) distortion and being an effects box. I tried the so called best measuring Dutch and Dutch speakers but they didn’t make a sound that fooled me into thinking real musicians were playing real music in front of me.
Measure all you want, define common expressions to suit your argument all you want, but in the last analysis it is about recreating a realistic illusion of the original sound, assuming it existed of course. That requires a subjective response because we, the final part of the chain are individual and perceive how sound fills our room differently. That, I find interesting to discuss. Perhaps the problem with some objectivists with an overly focussed view is that they keep on discussing that which doesn’t really need to discussed but can simply be stated.
Oh sod it! My system has stopped being realistic - the internet connection has started dropping out. Now that is hard, objective reality!
BTW, all the above is IMO and if it doesn’t apply to you, well tough!