Criticism, like rain, should be gentle enough to nourish a man's growth without destroying his roots.
-- Frank A. Clark
Clark's observation makes sense when you are criticizing from a position of power. Then your criticism needs to be as nourishing as a gentle rain.
But if you are in a position of power, you need to accept and welcome criticism as fierce as a driving rain. Why? Put yourself in the shoes of your critic. Criticizing a person in power is scary business. The only way the critic can criticize the person in power is to crank up his courage and spit it out. In that case it is not likely to come out gentle but it is likely to provide the leader, the person in power, with valuable information.
When George W. Bush ran for re-election as USA president in 2004 he made sure that his security people screened out every possible critic. They were very effective. Not once during the campaign was Bush heckled. After Bush's re-elction, his one purported critic within his first administration, Colin Powell, was out.
Subsequently, Bush missed important information from critics of his Iraq war policy until it was too late and he lost Republican control of the House and Senate.
The humble heirarchy leader knows that he needs the information provided by his fiercest critic.