I can really only speculate, but my guess would be that the higher-ups at Fox – like the higher-ups at any media conglomerate – are concerned primarily with making money. FoxNews is the only game in town when it comes to explicitly conservative reporting. Maybe those on the programs themselves believe what they’re saying. I have no reason to think otherwise. But I would suspect the higher-ups are concerned with being profitable moreso than pushing an agenda.
But this is all just speculation. My only basis is my own assumptions. I could very well be wrong.