A theater actor who constantly forgets or mangles his lines because he can't stand the repetitive and boring activity of rehearsing his roles... A mathematics lecturer who forgets to present simple but important lemmas, and who routinely messes up his blackboard calculations - all because he can't endure the mind-numbing and time-consuming preparations for his assigned courses...
I think that a reasonable person would have a healthy doze of contempt for such sorry "professionals" who willfully disregard the basic responsibilities of their profession. And this contempt would not be diminished by loud assurances that, although such "professionals" screw up the details of Shakespeare and Chekhov (or Gauss and Hilbert), they convey the big picture, the spirit, if you like, of Macbeth or Uncle Vanya (or the Fundamental Theorem of Algebra) better than most.
Yet when it comes to pianists, such unprofessional behavior can be looked upon with tolerance bordering on affection, or even adulation, as witnessed by the axiomatic inclusion of Cortot and Schnabel among the so-called Great Pianists. This is not about wrong or missed notes per se. This is about the easily recognizable difference between wrong notes as neurophysiological accidents (which can happen to any musician) and wrong notes as the predictable consequence of willfully keeping one's technical equipment in the state of sad disrepair.