Did you read that link you posted?
Because that link does not claim it was Carnegie, who thought he was quoting Franklin. Your link claims it is from an 1815 source, by Robert Walsh.
Lol...you really know how to screw yourself over. Read it again, and try to not get confused this time.
The Robert Walsh reference refers to this quote:
I will speak ill of no man, not even in matter of truth; but rather excuse the faults I hear charged upon others, and upon proper occasion speak all the good I know of everybody.
"Any fool can crticize, condemn and complain -- and most fools do."
Benjamin Franklin
Too bad that's a Dale Carnegie quote ;)...
http://rationalrant.blogspot.com/2011/07/fools-and-criticism.html
http://en.wikiquote.org/wiki/Benjamin_Franklin (check under the "Misattributed" section)