Why did the governess report that “there could be no question of punishment” with Tchaikovsky?

With him there could be no question of punishment: the least criticism or reproof that would pass lightly over other children, would upset him alarmingly."

Explanation:

When we read together none listened so attentively as he did,  and when on holidays  I  gathered my pupils around me in the twilight and let them tell tales in turn,  no one could improvise so well as  Peter  Ilich.  I  shall never forget these precious hours of my life.  In daily intercourse, we all loved him,  because we felt he loved us in return.  His sensibility was extreme,  therefore  I  had to be very careful how  I  treated him.  A  trifle wounded him deeply.  He was brittle as porcelain. With  him  there  could  be  no  question of  punishment;  the  least  criticism  or  reproof,  that  would pass  lightly  over  other  children,  would  upset  him  alarmingly."

Hope this helps.