You are confusing “greatness” with notoriety.
Not really. I don’t think you can argue that Julius Ceaser was not a great political leader, despite killing millions of Gauls. Napoleon was surely a great political leader as well. Just examples, but despotism has been the norm throughout history, so most great political leaders have not been particularly interested in human rights, and have been judged by the omlets they made, not the eggs that were broken along the way.