SWriverstone -- This was your introductory statement in your initial posting. If you will allow, I wish to bring forth an opinion.
I feel that I must disagree with this, based upon the final 5 words of the statement -- "...you'll start thinking it's good." As you initially postulated, "It means people develop a preference for things merely because they are familiar with them." Fair enough...I have no problem with this -- in fact, I would tend to agree. Simple enough. However, there still remains a large difference between liking something due to familiarity, and thereby also thinking it's good. One is quantitative in nature (preference through familiarity); the other is qualitative (thinking it's good). Please allow me to go off-topic for a moment, for the purpose of illustration...
As much as I hate to admit it, I am a smoker. I smoke because of 1) the addictive nature of the nicotine; 2) the apparent relaxation it brings me in times of stress; 3) the simple effect of habit. Such action on my part does not mean, however, that I am also convinced that it is "good." It is not, and I know that. It's unhealthy. It's expensive. It's unclean. Despite all of that, I still smoke. Maybe -- no, certainly -- all of this speaks more to my lack of will-power and sensibility than it does any inherent judgement on my part of its' detriments.
What does this have to do with one's personal judgement of the "goodness" (qualitative judgement) of a work of art? Everything. I can like a particularly dirty, obscene, morally indecent joke based upon...or despite...its' relation and/or adherence to societal standards. I can also fully acknowledge that it is something which is not "fit" for common consumption to a segment of society. I, too, am a musician, going into my 38th year of teaching in the field of Music Education. As I stated on a simple post earlier in this thread, "I like what I like because I like it." When I reach that point, I am not necessarily stating either as a teacher of music or a mere observer outside the field of education. I am stating no opinion as to the relative quality of a given piece of music in an artistic sense. It is much akin to when any of us laugh when we might be exposed to a particularly bad joke or pun. Sometimes we laugh (possibly even "like" it) based on the lack of quality of it. How often do we laugh, then follow our chuckle with "that's SOOOO bad!!"??
I know what I feel is "good" music...what I've been taught as being such. And I know "bad" music...that is to say, what I've been taught to consider "bad" music as being. But I also know that these qualitative judgements -- AND quantitative judgements -- are MINE, and designed as MINE alone. And yes, sometimes I find myself listening to music because I like it...even music which I might not consider to be of "good" in quality. There may simply be something about it which piques my attention -- even if the overall selection, taken as a whole, is something which I would place outside the "good" (qualitative) category. Maybe it has a wonderful melody, but is dry harmonically. I might find it lacking of value melodically and harmonically, yet I find a degree of intrigue in its' rhythmic underpinnings. In terms of Drum Corps, maybe it might be Jim Brady solos in "Spanish Eyes" or "Pagliacci." Maybe it's Barbara Maroney's concluding statement in "A Boy Like That." Maybe it's Zengali's/Star of Indiana's "Cross-to-Cross." Maybe it's the simple, brass-player's thrill to Madison's power and (excuse me) "balls forward" rendering of "Malaguena" in 1988. And maybe it's nothing other than the Bluecoat soprano soloist's "wink" of a couple of years ago. Those two seconds didn't get points. They didn't get GE. But as a brass player, I could both get and admire his internal affirmation of feeling "so THERE!!"...with an accompanying wry smile. Whatever. I can "like" it, yet also do so without any...ANY...consideration to anything other than a most simple...and most human..."WOW!!"
Yet...in the end...I "like" it. And to be honest...that's all of which I care. At that point, it is not up to me to educate. Instead, it is merely up to me, as an individual member of the human species...by-and-large, one individual member of a very individual and imperfect human species...to determine of and for myself to "like." And to enjoy.
Quite honestly, Sir...that is something of which Julliard...or Eastman...or any Conservatory/School of Music cannot teach us, whether we have the great fortune to attend or not. To ultimately determine what we "like." In the end, as human beings both educated and musically-uneducated alike...we like what we like because we like it.