If a philosopher or any thinking individual thinks an act is moral or not, then should that apply to everyone in the world equally including his own family members? Suppose he thinks performing in pornographic films is not immoral, then should he think any less of his daughter who decides to do so?
Morality is generally taken to be different from subjective taste. If I think something is right then that claim is taken to apply to everyone, whether they know it or otherwise. I may respect those who differ from my opinion, but still think their action is immoral. Whether someone is in my family or not is irrelevant.