The motive behind criticism often determines its validity. Those who care criticize where necessary. Those who envy criticize the moment they think that they have found a weak spot.
My father taught me that you can you read a hundred books on wisdom and write a hundred books on wisdom, but unless you apply what you learned then its only words on a page. Life is not lived with intentions, but action.
Constantly stopping to explain oneself may expand into a frustrating burden for the rare individual, so ceasing to do so is like finally dropping the weights and sprinting towards his goals. Those who insincerely misunderstand, who intentionally distort the motives of a pure-intentioned individual, then, no longer have the opportunity to block his path; instead, they are the ones left to stand on the sidelines shouting frustratedly in the wind of his trail.