Now where's your proof that O'Reilly is conservative and would always vote that way?
I don't have any proof. But he takes a right of center stance on lots of issues. Not far right, but definitely right. If he votes for a liberal, it goes against everything he says he stands for.
In the end, the only time he might vote against a conservative is if there is a less conservative conservative for him to vote for. It might mean he'll vote for a conservative Democrat, but I do that sometimes too.
Conservatives aren't all far to the right. Conservatism is based on a philosophy of slow, measured, results oriented steps. Conserving as much of tradition with every step forward as possible, without sacrificing progress. Resisting extremism. The far right are like the far left. They are the extremes. Liberals want to rush ahead and create a utopia with the force of their ideals, the reactionaries want to stay where we are or head back however many years they think necessary to head back to where they feel most comfortable. The conservatives are right of center, the progressives are left of center, and centrists are in the middle. O'Reilly is not a liberal, he is not a progressive. He is a centrist conservative. He is a centrist because of his cultural progressiveness, but he is a conservative because of his politics.
Even if he is not as conservative as you does not mean he is not conservative.
As for proof, do you know if he's ever voted for a liberal?
My statement was rhetorical, and the only way to disprove me is to show that he voted for a liberal. He doesn't get along with liberals, so I doubt he's ever voted for a liberal in his adult life. He's conservative friendly, anti-liberal. Is there anything in there that would suggest he'd vote liberal?