Once we viewed a film, yes, it would be ethical to judge it honestly, i.e., according to whether we enjoyed it or not (the only "merit" that counts in entertainment). But as to the decision of which films to watch in the first place, there's no obligation to consumers to treat film co's, directors, or actors "fairly." It's a marketplace. The only thing that matters is whatever consumers think matters.
IF you couldn't envision investing one penny to help support a company on account of a CEO you personally detested that would be fine. That's how it works whether we are voting with our wallets or with ballots. [Did President Obama get elected on merit? I'd say that in addition to race likely playing a part, he primarily got elected because of his oratorical skill and brilliant campaign team coming up with the meaningless cliche "hope & change" that people would rally around.] Anyway, if Santorum ends up treating the company's funds the way he did taxpayer money, I don't think he'll be CEO for long.
When we try to pick out anything by itself, we find it hitched to everything else in the Universe.
~ John Muir