I think that you are under-estimating the emotional connection of tribal life. How can you not feel emotions if you live around someone and your economic/survival activity is interconnected? You are all up in their business, you hear everyone fucking, you see all of the nonverbal communication all day, etc etc. Have you ever like, gone to camp? Or lived in a student residence or something?
I think she's overestimating the emotional component of tribal relationships. The deep emotional connection is a romantic concept that occurred simultaneously sometimes but not prior to having sex in the tribal context.
"Ah, those endless forests, and their horror-haunted gloom! For what eternities have I wandered through them, a timid, hunted creature, starting at the least sound, frightened of my own shadow, keyed-up, ever alert and vigilant, ready on the instant to dash away in mad flight for my life. For I was the prey of all manner of fierce life that dwelt in the forest, and it was in ecstasies of fear that I fled before the hunting monsters."
Jack london, "Before Adam"