A lot of times getting someone to see your point of view, if it's an ethical thing, is not about changing their heart it's just about them saving face. If they give in to look good, they'll always blame you for being the source of the embarrassment. One day they might break down and revoke their agreement, get angry at you for forcing them to adopt a position they didn't really want to. If their embarrassing stance had a religious source, a part of them will always be apologizing internally for going against it. When that contradiction gets too severe, it will break and it will be your fault for causing it.