Exactly, serial music requires more of the listener, that doesn't automatically make it bad, in fact such a view would amount to the view of music held by your average pentatonic rock fan.
Specifically, it demands that a listener bring a boatload of theory and self-righteous pretense with him to the show: it's basically aural jargon, orchestral Newspeak, if you will.
This is misinformation, the basics of serial music can be taught to someone with only rudimentary musical knowledge in a few minutes. Even the basic ideas of classical music take years for most people to grasp.
Also, for all those who think serial music came out of nowhere, it didn't. It is basically a return to the linear organisation of pitch that was present in music right up to the baroque era, also serial theory is directly related to the medieval isorhythmic motet
The real reason I'm playing devils advocate here is not because I have any great love for modernist music, but to underline the fact that the philosophy of art proposed by many on this forum, a sort of awkward combination of structuralism and romanticism, is not consistent with itself, and this is why no one here ever manages to mount a valid argument against modern music without contradicting themselves. What is needed to reach a more holistic understanding of music, and for that matter art in general, is the realisation that sounds have innate qualities, and the understanding of these qualities is vital to music making. This understanding is present in an indirect sense through the whole western classical tradition, but it disintegrates in romantic music and is completely abandoned in the 20th century, not to say all 20th century music is bad (Webern
is awsome). The real problem for western music was always equal temperment and an excessive focus on abstract theory, which makes people forget about musical qualities, this is why medieval and renaissance music are generally better than music from later periods.
Structuralism and romanticism are half-truths, its impossible to construct the whole truth out of them, what is needed is a direct insight into the nature of music itself.