When smart people say stupid things II

I have become completely dissatisfied with [serialism's] narrow terms.  I found the palette of constant chromaticism increasingly constricting, nor could I accept any longer the limited range of gestures that always seemed to channel the music into some form or other of expressionism.  The over-intense manner of serialism and its tendency to inhibit physical pulse and rhythm led me to question a style which made it virtually impossible to express serenity, tranquility, grace, wit, energy.
George Rochberg, liner notes for the 1973 recording of his Third String Quartet issued on Nonesuch Records LP  (italics mine).
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I happen to like Rochberg's 12-tone music (2nd Symphony, Piano Trio) and I have no problem with his decision to abandon serialism (by which he means only serial organization of pitch, not integral serialism of Babbitt, Boulez, and Stockhausen) in favor of (mostly) tonal composition.  But his attempted justification of this decision strikes me as borderline incoherent.