Why is Nixon's moral relativism on abortion so shocking?

I intersperse my comments in red with those of Bill Donohue of the Catholic League.
A news report shows that when the infamous Roe v. Wade decision was granted by the U.S. Supreme Court in 1973, President Richard M. Nixon worried that abortion would promote “permissiveness.” But he also thought that abortion would be justified in cases of interracial pregnancies. “When you have a black and a white,” he said, “abortion is necessary.”
No one in the pro-abortion camp has any principled reason to object to Nixon’s selective justification for abortion. Indeed, pro-abortion advocates cannot logically claim that abortion is morally neutral and then object to abortions for reasons they find objectionable.
Who are they to decide what is a good reason or a bad reason? Who are they to decide that a woman’s right to choose must accord with liberal rationales for abortion? Ultimately, if extracting a baby from a mother’s womb is the moral equivalent of a tooth extraction, then all abortions are morally equal.
Remember a while back when liberal gays learned that a “gay gene” may exist? They were scared to death that prospective parents might elect to abort such kids. Now we have the prospect of those who will condemn Nixon on this issue. I was at a bioethics conference at the UN when a gay man said that it would be discrimination to abort because of a gay gene, but that killing my daughter with Down syndrome would be necessary. You can imagine the rebuff he received from me!
Ironically, the man who sits in the White House is just the kind of guy Nixon thought our society would be better off without. That the current occupant is also a pro-abortion extremist makes the story all the more bizarre, if not sickening.
So the moral relativists in the abortion lobby want free abortions, paid by the taxpayer, except if 'gay' babies are aborted. Sounds like Nixon all over again. Once you throw out natural law which tells us in our heart of hearts that abortion is always murder, any bigot's opinion is as good as any other.