If there can be said to be any "origin" of so complex a
phenomenon as binary thinking (as a syndrome & not as
a procedure), i think it must be in parental malpractice, by
parents similarly afflicted, who are incapable of unconditional
love & thus force their children to suppress part of themselves
which will be a long time retrieving (if ever); in the meantime,
they will have to be some sort of dualist, although the exact form
of this may turn out quite a heretical one.

If every time the word "evil" was used by someone who should
know better was the playing of a song, & i got royalties for that song,
i wouldn't have to work at this bookstore, that's for dingdong sure.
It's theology, it makes about as much sense in any discussion
about the real world as requiring all of us to invoke Mickey Fucking
Mouse in the news. And do you know why it's so convenient to
have this word at our fingertips? That which is "evil" is a Monster, &
a Monster's feelings don't count. You don't try to persuade Monsters,
you exterminate them. --And what is a crusade against crusades, but
another kind of Monster?