There're any number of reasons why someone might visit those countries. When you put up $1K towards a political campaign whose raison d'etre is to deny gay people the right to marry, it's rather well defined what the expectation is.

I don't understand what charities have to do with this, though. Surely there are charities which would be morally objectionable. If he'd donated to a charity with similar aims to the Prop 8 campaign, I imagine it would change people's opinions rather little. Or how about a charity which campaigned against interracial marriage?