What distinguishes gibberish from sense is much more objective than what is "pleasing".
The amount of music where this is true as a result of the brain's actual ability to perceive information is likely to be marginal. Cultural indoctrination is definitely an issue here: To the ear untrained in its practice (i.e. mine), much Indian classical music sounds remarkably the same and more or less inscrutable. As it turns out, there are well-documented accounts of the highly organized rules used in this music, and how to anyone intimately familiar with it, the "rules in play", so to speak, are immediately obvious based on context, creating an idiomatic framework in which to explore and enjoy certain musical ideas.
I also once perceived Western classical music in a similar manner. There are of course, the "hits" that everyone knows, many of which are from the Classical period whose aesthetics prized simplicity and clarity, but beyond that, we have the early, the Medieval, the Baroque, the Romantic, and the modern flavors of "classical" music (and more, still!). The more I learned about music formally, the more easily I was able to discern the qualities of certain styles and periods, and going even deeper, individual composers. Despite coming from a background of metal and avant-garde progressive rock, genres which often revel in dissonance and complexity, much of modern classical music confounded and repelled me. At this point, I have gained a large appreciation for much of this music and have discovered the basic ideas which most tickle my fancy within this realm, and have pursued them and found that as I've gone on, my tastes have continued to expand, allowing me to appreciate even more related music which previously might have bored or offended me.