However this doomed little boy came into existence, he has a natural father out there somewhere.
That natural father is AWOL for whatever reason. He's the sperm vendor (oops, "donor") who disappears after he pocketing his pittance for his 5 ml of fatherhood; or he's the drunken hit-and-run inseminator, or the bye-bye husband (unlikely, with the lesbian dam, but possible) ---
For whatever reason, as I said, he's a gone dude. Thus he is, will-he or nill-he, one half of the problem.
The child has a natural right to his natural father for identity, for one half of his kinship universe, for providence, and yes, for protection.
The fact that the natural father never assumed his obligations, is part of the reason why this little boy is dead.
I agree that his irresonsibility contributed in some measure to the situation these unfortunates found themselves in, but he did not beat them, torture them, and finally kill them. He just left them to be be beaten, tortured, and finally killed.
So yes, he is as big a POS as the deviant sadists who snuffed the life from that child, but his was a sin of omission. He was notable only by his absence.