Kinda intersects with Prager's first cause
To paraphrase: Ozzie's fan base is likely to be mostly "progressive" (a.k.a. damn libruls.) So he can't be popular with them while being in conflict with the librul catechesis, where the extreme Bush bashing, no matter how preposterous, is de rigueur at the moment. The fans will shun him. And since most of such popular figures' (Moore, Ozzie, Streisand, Dixie Chicks, et al.) income -- and possibly, though not necessarily, identity -- comes from pandering to their audience, being ostracized from fellow libruls spells a significant loss of popularity and therefore revenue.
Bush=Hitler? He's a rich guy and should know better than that. For him there's no excuse to be stupid, which means he's an irresponsible hypocrite.