He probably hates his rich father, and has resented him all his life.
He went after the 77 year old Sen. Bruno, and called him a "Senile piece of Sh^t!"
He went after the big wigs on Wall Street who were in their late 70s and 80s.
He definitely has an "authority" problem.
While reading an article about Spitzer’s fall from grace, I made the same mental note about his abusive behavior toward older authority figures. I just didn't tie it to his relationship with his father.
But it makes sense.