Why Does BILL OREiLLY Pretend to be Indy?

Does he say he's INDY Simply because he does not act obnoxious? I mean He is clearly the most well mannered person on the Network ( Even though he does it live!). But My honest question is. Why Doesn't the man just admit he is a moderate republican? I mean seriously, He only argues with Liberal guest. He's always defending the Right, defending the Tea party, And he says' " LEFT WING LOONS" Like 50 times a night. The majority of his guest are Republican. And Whenever he has a Liberal Guest, He typically confronts them and ask's them questions like " So, Do you Regret supporting Obama in 2008"? I dont Remember him asking any republicans the same question about Bush. He says that same line to every Democrat who is on his show.