What exactly is the reasoning behind placing Clinton in the top 5 worst? It really makes little sense; none of his actions cause anything to collapse. The lone real criticism of him from the right seems to be that he let the Islamists prep for 9-11 in the '90s while ignoring the threat, and at best that's just an accusation.
There are so many who are obviously worse than him.
I agree that there were many worse in terms of policy. I think there were probably only a few, if any, that were worse in terms of character, and in terms of placing the public interest over his own private interest.
BTW, I did not list Clinton as one of the worst.
Character is more of a judgement call than anything else. It's hard to judge as we really don't know these people.
But off the top of my head I think Harding, Kennedy, and Nixon had worse 'character' than Clinton, and if I had to I could name some more I suppose.