“Any fool can criticize, condemn and complain -- and most fools do.”

Some complain who are not fools.

The statement, on its face and held as a stand alone quote is accurate enough. The statement simply doesn't cover the whole subject. As for personal experience; I have been criticized by brilliance and grew from it. Some actions have been condemned and complained about and my knowledge and understanding increased. Those who have directed criticism, condemnation and complaints at me have covered the gambit from fools to brilliant.

I think what Carnegie was getting at is that we need to ACT in order to correct the ills of this world.