Gene, in 1983, I added an audio out from the incredibly crappy black & white TV I owned by adding a feed from the speaker to my stereo. While it didn't sound great, it sounded way better than the TV speaker. My Marantz pre had a knob for stereo/reverse stereo/mono/left/right so switching to mono was a breeze for TV audio.
I now have 3 audio systems in my house: a Polk Magnify Mini hooked for TV and wireless audio in the kitchen (love watching crappy Netflix content while I cook), KEF LSX's and cheap subs in my bedroom for TV and audio (great for listening to music while I shower or lift weights in my upstairs home gym) and a home theater in the basement.
Around 6 months ago or so, I posted a response to an article at a site much like yours (or maybe it was yours) and I mentioned something about the questionable audio quality of some streaming sources in my home theater. In reply, the
journalist made a crack about the quality of my XMC-1 pre/pro and pre/pro's in general.
In response, I reminded him that, a few years earlier, his web site tested the Emotiva box, gave it a great review and named it one of their products of the year.
He did not reply to my post. He played himself.
So, given my experience, I can't offer you any reason other than blatant stupidity and ignorance. If a pre/pro has vanishingly low levels of distortion & noise, how does it sound worse than a stereo component? Also, unless you're an analog luddite, most modern stereo pre/amps and integrateds offer digital inputs.
Hey, we could also get into why people like noisy, distorted vinyl records and tube amps, but there is no accounting for people being imbecilic.
Let them soak in their own morass. That doesn't effect me at all.
All of my systems are very good for what they are. If other people have strange predilections, that's their bag. I wouldn't sweat it if I were you.