Two different things here

No, the guy would never have been happily involved with her. If he had any desire to do so, he would've done it - after all, the law was no deterrent to him. He wanted to abduct, rape, and kill her. Period.

(The above, of course, assumes that the suspect is indeed the perpetrator)

In this sense, no SOR reform or AOC reform would have prevented this.

OTOH, you are right that the SOR gives parents (and children, and in general people who are not psycho) a false sense of security that leaves them less able to deal with this much greater danger than that posed by the overwhelming majority of those who are in it. This is precisely the crime that the SOR is sold to the public (and parents especially) as preventing, and it sure didn't prevent it. You are 100% right on this one.

And yes, whoever did it, the current suspect or not, deserves being decapitated with a teaspoon.