I think you should really take a step back and consider what you're saying here. Do you really think that arbitarily eliminating whole demographic groups is a good way to control crime?
I'm not suggesting it as an action plan people should discuss and then adopt. I'm saying that there is statistical evidence that it
happened, as an unintended consequence of a large number of individual decisions. No single woman said "I'm going to have an abortion to control crime." But many women had abortions as an alternative to having children they didn't have the resources to care for, and as a side effect, urban crime has been on the decrease.
I'm not advocating abortion here. I happen to consider it weakly unethical. (I explained my theory of "strong" vs. "weak" ethics in a different post some while back; I don't have the energy to go into it again.) But if you're going to argue against it on pragmatic social grounds, as you attempted, there's a more complex picture painted than a simple "It's devastating society." Very little in this world has consequences that are purely good or purely bad.
But isn't that the whole idea of morality? Different people have different opinions, but morality transcend those opinions and gives everyone a common standard. If morality is merely a matter of individual opinions, then "morality" means nothing at all. Morality that does not apply objectively is not morality at all.
My main observation here is that you seem to be using a definition of "objective" that is awfully... Well, I was going to say "subjective" just to be symmetrical, but "selective" is probably more like it. What is this objective source that should, in theory, be keeping the entire human race on the same page?
And please don't say "the Bible." It cannot possibly have escaped your notice that different people have different ideas of what the Bible means (there have been wars and movies about that too), nor that there are moral creeds in it that nobody takes seriously anymore. There's plenty of death and slavery and racism and sexism and sheer bloody-mindedness in the Bible, alongside the love and the goodness and the wisdom. Not to mention that the contents of the Bible itself were decided by committee in a highly political process many centuries ago. To say, "Yeah, but we've picked these good bits as the ones that are important" -- is that really being objective?
(If that's
not where you intended to go, then my apologies for the presumption. I was just hoping to save some time.)
Please don't misunderstand: I'm not anti-religion, at least as a generality, and I'm certainly not anti-morality. I like people with strong ideas of morality. I like people with strong ideas of good behavior, who live by those ideas and are good toward other people, regardless of where those ideas came from. The danger is when that conviction leads to
hubris, and to believing that one has all the answers for everyone.