Isn't innocent vs (theoretically) guilty an easier explanation?

Yeah. I think it's about sin and Calvinism. The unborn are sacrosanct because even with original sin they cannot have exercised will sinfully. Everyone else is up for grabs because most people are sinful, everyone dies, and only a few are saved.

I’d argue control is a simpler explanation

same idea but more limited as convicted criminal falls under undesirable and innocent otherwise