However, there is one distinction that Bush has that none of the others on the top 10 have. Only he launched a war against a sovereign nation thousands of miles away while in the position of head of state. Granted, several of the others did not have the technology to do so in their time (Genghis Khan, especially), but he is the only one on the list who did it either way. Others were also not formal heads of state (Khan again, or Bin Laden for a more recent example).
I expect you might want to counter with something along the lines of how Bush believed he was doing the right thing by invading a sovereign nation thousands of miles away who posed absolutely no credible threat to his own country. To that I will also point to the fact that the others on the list mostly also convinced themselves they were doing the right thing.