Really? The source of slurping? I'd dare you to name a good source of this fine sound, but I'm a little concerned what I might get back. I'll just take your word on it, coathanger-man.
I've noticed this in my own life. I don't think i'm a genius, I think people just have different sensitives to it. I noticed it when I was a kid, it's hard to explain without sounding like a creep. When I was a kid, there was this gentle old man that was friends with my family, he would come over to the house and one of my favorite things was listening to him talk, if it was quiet enough and all you could hear was his gentle voice, it was almost mesmerizing. Every little nuance, syllable, and breath.
Again, trying not to sound like a weirdo, just being honest. Nothing sexual about it, it was just a warmth.
Later I noticed that if men were around (i'm a guy) and I could hear anything intimate, i.e. their breathing, their chewing, them whispering or even talking in a low tone, it was incredibly annoying. To the point I would get up and leave in that situation.
Children don't have that effect on me, or women. If I'm with a woman somewhere and she's whispering, or eating and I can hear it, it doesn't bother me at all.
I don't think it has anything to do with hearing, I think it's some primal thing about control or some crap, I don't know. Very weird.