Well, part of it is that Quirrel is Voldemort in canon, which is significant evidence that Harry doesn't have.
I don't think it's a good idea to do a formal memorization of something that's not based on any kind of scientific research.
On the other hand, one should consider not only what was said, but also what should have been said.
Neutral plot possibility: usually, dying minds aren't felt in the wizarding world. Something unusual was going on, and I don't know what it was.
This seems unlikely. There was a mention about ghosts being caused by "the burst of magic that accompanied the violent death of a wizard" (or something along those lines -- I don't feel like looking up the exact quote right now.)
Counter-evidence: Harry produces blue and bronze sparks at Ollivander's.
As long as we're sticking necks out, though:
Definitely: The horcrux technology uses the ghost phenomenon. Specifically, by causing the violent death of a wizard under controlled conditions (i.e., murder) it's possible to harness the powerful burst of magic to make a ghost of the living caster instead of of the dying victim: a backup copy. A ghost may be static data rather than a running instance, but hey, so is a cryo patient.
Definitely: Baby Harry was overwritten with a horcrux-backup-copy of Voldemort. Voldemort didn't plan on childhood amnesia, though, and much of the information was erased (or at least made harder to access consciously). The Remembrall-like-the-Sun indicated the forgotten lifetime as Riddle. Remnants of Voldemort's memories are the reason Harrymort has a cold side; his upbringing in a loving family is the reason he has a warm side.
Mere hunch: In chapter 45, the Dementor recognized Harry as Voldemort and addressed him by name: "Riddle".
Mere hunch: Voldemort may have chosen to impress his horcrux in a living human in order to try to get around the "static data" problem. If it had worked, he would have forked himself -- there would have been two fully functional running instances of Voldemort, all the time, plus twelve hours a day worth of Time-copies.
It's not obvious to me how to fake the soul releasing. It was perceived by the magic-sense, not just with the muggle senses.
That's a good point, but I'm still not convinced.
Hugging is, potentially, fast: if A tries to hug B and B pulls away, a hug has still occurred. Sex takes longer: there's complicated steps involving disrobing and so forth. Your argument applies to, say, groping; but if B doesn't want to cooperate then that becomes relevant before sex has occurred. It's clear ("safe", "take matters into her own hands") that there is not a reliable way of getting out of sex.
Also, the dialogue ("Prohibition", "too much") seems to suggest social acceptance.