All I can see is that this person, whoever he is, is not a total loser in the community, but his view of the community is very condescending.
The girls themselves were successful and smart, but as the BG thought, might have some been of a lesser social standing than himself. (Both came from incomplete families, for example). To some, the fact that the girls were “good girls”, athletic, had good grades, tried so hard to succeed, would have been the reason for personal respect. This perp respects people for their standing, not the job done to achieve. He is a total misfit for the role he performs, but this is not noticeable because outwardly he is humble.
I think that this person, BG, deep inside, holds a very rigid view of how the community works. Where a local doctor, lawyer, minister, as well as municipal bodies and to the extent, the police, are on top, and the rest are necessary for their existence, but ...expendable?
MOO - it shows in conversations, in some primitive way, like “a doctor’s wife should wear pearls”, or something equally archaic (our society is moving to influential people dressing down, not up). It must, the way I imagine him. And - he came to attack the community he knows. Because he knows the way out, but also, he knows “who is who” there.
And if he is a person of some standing, there should be a disconnect between what he is doing and how he speaks. If a priest, he’d speak only about Jesus, if a doctor, about his last golf score, etc, etc. He is not able to talk to people about their personal issues. MOO
I don’t view someone special in mind, I am wondering how he thinks. MOO
Another feeling - he may be having occasional psychosis, some violent thoughts and he doesn’t know where they come from.