But look how they differ from objectivism or how they converge in practical situations.
To the objection that moral objectivism implies intolerance (or imperialism), objectivists typically contend that the fact that we regard a society as morally wrong in some respect does not entail that we should interfere with it
Perhaps the conjunction of MMR and an ethical principle could give us a reason for tolerance we would not have on the basis of the ethical principle alone. Such an approach has been proposed by Wong (1984: ch. 12). The principle is, roughly speaking, that we should not interfere with people unless we could justify this interference to them (if they were rational and well-informed in relevant respects). Wong called this “the justification principle.”
Let's see the case of parent's right vs grandparent's right.
Petitioners Troxel petitioned for the right to visit their deceased son’s daughters. Respondent Granville, the girls’ mother, did not oppose all visitation, but objected to the amount sought by the Troxels. link
A lower court judge granted the grandparent's petition.
I look back on some personal experience...We always spent as kids a week with one set of grandparents and another set of grandparents, and it happened to wrokd out in our family that it turned out to be enjoyable experience. May that can, in this family , if that is how it works out.
The Supreme Court of Washington reverses that ruling and struck down that law on the ground that it "unconstitutionally interferes with the fundamental rights of parents to their children.
The United States Supreme Court resolved the case by resorting to process and procedure.
Because the Washington statues did not accord sufficient deference to the wishes of the custodial parents and because it authorize "any person--"---no only grandparents---to partition for visitation, it was held unconstitutional.(Rights From Wrongs by Alan M. Dershowitz page 107)
The court differed in opinions, and in a way the Supreme court avoided judging which view is right;it does not touch on the issue whether a child's best interest overrides the parent's right, but the court settled the issue by appealing to the process and procedure or the lack of it.
In this case the interference with grandparents' right was justified because there was lack of proper procedure to the mother.
On the level of the court decision, the interfrance was justified because both parties had an access to the fair trial and both parties had the same value to the court system.
When we turn to the international issue, the problem is more complicated; because there are countries that do not share the value of the international court system or the some sort of international
community by which the issue is settled.