Not in public, no. However, he was a dick to them in private where he though it'd be safe. Prop 8 was about taking away a right that gay people had. They were already allowed to marry. This was about the majority ganging up on a small, persecuted group and taking things away from them by legislative fiat. The Constitution forbids this, as was later confirmed by the courts.

If Prop 8 had been about re-enslaving blacks, and he'd donated to that, do you think we'd be saying, "well, but he's nice to all the black people he works with!" It was morally repugnant to support Prop 8, and public acts like political donations do, shockingly, have consequences.