The Lord Acton quote

Almost everyone, especially historians, has heard ad nauseum Lord Acton's quote "“Power tends to corrupt, and absolute power corrupts absolutely."

What I didn't know until today when I read a column by Charles Blow that the next line to this quote, the part almost always dropped, is "Great men are almost always bad men.”

Now why is that part usually left out? Is it just too awkward to tack on, or does it make the quote too long and less striking?

Or is it because we all have our "great men" we want to admire?

great men like Vlad the Impaler? Or Ivan the Terrible? Your own personal choice?