That's Bad for the Piano!

As far as classical music is concerned, the 20th century has seen a broadening of what can be considered "music." Music is still, in most ways, organized sound but how that "organization" is perceived has changed. Aleatoric music is based on chance but is justifiable as "organized" sound in some ways because there is an organization to the process. It is based on random elements but not completely random. But modern "classical music", including pieces that call for trying to push a piano through a wall, isn't a pioneer of exploring what can be considered music. Early explorers in organized sound surely had broader boundaries for what can be considered music than modern faux zealots who might insist that "rap" isn't music just because it doesn't conform to the most banal examples of a melody supported by harmony all within the equal-temperament diatonic scale system. (And even there, the bassline, hooks, and harmony of most rap is purely diatonic and there is a cadence pattern of highs and lows that can easily be considered melodic.)

An extension, or perhaps parallel, of this kind of intolerance is stipulating how instruments "ought" to be played. Stravinsky started a riot with his Rite of Spring not so much because of the supposed vulgarity of the ballet and its choreography, hump-dancing a virgin to death and all, but because of the way the instruments were being "treated." There was pitch dissonance but also timbral dissonance as ferocious bowings were called for in the strings and obscene and strident blowing (har har har) called for in the winds. The Rite of Spring, of course, prevails as an innovative masterpiece and much of its materials remains astoundingly fresh even today. It explored new ways to produce new sounds from existing instruments and, more importantly, it did it convincingly.

Moving out of the realm of classical music, pop musicians who use instruments that overlap with classical instruments are also often accused of abusing their instruments (though not by the people who actually like their music, of course). One prominent example is Ben Scott Folds of Ben Folds Five fame. He has a pounding style that would be the nightmares of countless classical piano teachers. Yet his talent is indisputable. It's just that he has a different style. He sometimes steps on the piano, he sometimes uses his fists on the piano, and he will sometimes take his chair and pound the piano with the cushion by throwing the chair at the piano almost as a spear. Sure, it's not the best way to keep a piano in tune but if it's done for a reason (and not out of pure lunacy), shouldn't it be fine? After all, isn't Ben Folds just playing triple sforzando tone clusters? And what better way than with feet (broader than the hand) and fists (stronger than individual fingers)?

Of course, those that would balk at stepping on the piano might also balk at modern classical music as being unmusical.

No.

You can say you don't like it and you can say that you don't understand it but if you want to get with the times, never ever quickly label anything as "unmusical". Music is everywhere. Why limit yourself?