"there are no videos and no evidence of slow hanging" - below 3 links are just from first page of Google search, widely available. I didn't even search specifically for slow hanging, just hanging.
You are hugely mistaken if you think all hangings are quick blackout. You guys only take theory about carotid compression, but practice differs from theory. Even from statistical point of view you are mistaken. In theory people falling from 30m onto concrete should die ALWAYS, but it doesn't happen. There are so many variables you cannot account for (and it's true for most methods).
I have seen hundreds of hanging videos (I am subscribed to many similar websites and check them daily). Many of them were quick, but you are oversimplifying things saying 5kgf is enough to block carotid - it's true in theory but often wrong in real-world practice.
Yes, with 5kgf of force (in theory) if someone doesn't have fat tissue on their neck, a person loses consciousness quickly, when both carotids are blocked. You can see it in MMA when done properly - it needs to be applied very specifically to the sides of the neck.
However many suicide hangings are not biomechanically ideal, because of:
-poor force distribution: rope position is asymmetric, pressing often one side or under the jaw, not ideally both carotids
- head or angle posture (eg. leaning foward or sideways) makes symmetrical artery compression inconsistent
- vascular redundancy - sometimes only jugular veins are compressed, not the arteries, leading to venous congestion, swelling and slow suffocation, not a quick blackout
- not enough force (5kgf per carotid) may not be achieved with low-drop bodyweight, especially true in partial suspension
Also you said body examination does not tell anything, which is not true: quick blackout victims doesn't have claw marks, convulsions, vomiting, even regaining consciousness, on top of that autopsies show massive petechiae, tongue protrusion, cyanosis - all of these are signs of prolonged aspyxia, not carotid-induced blackout.
Another proof is that during some autopsies, ligature marks are observed not over carotid zones, but high under jaw or back of neck.
You have to differentiate blood choke, which is precise, applied by trained person and hanging, which is imprecise, passive, relies on gravity and luck. Hanging isn't a blood choke. The forces are different and the body isn't cooperating - it's panicking, seizing, writhing. Many real-world suicides fail to replicate the ideal conditions.
So, is carotid compression possible without a long drop? - Yes, of course.
Is blackout within 15secs guaranteed? - Absolutely not.
Anyway, I won't look here anymore, so seems like we both made our points and neither of us is going to change their mind. Let's spare ourselves some time and there is no need to drag this any further.
Take care, and good luck out there