This cackling Hillary is really a weird bird. I think she is seriously unbalanced.
No, she is seriously diabolical.
I recall seeing her apologist spin people behave this way for many years. When defending the obviously indefensible during Travel Gate, Cattle Gate, et al, they would present a barely contained laughing behavior as the news host questions them about some unbelievable point they were trying to maintain. Mandy Grunwald comes to mind but there were others.