How many students, or even certified divers struggle to tell their buddies, friends, even family members apart in a group of divers.... Someone could be right behind or right above you and for a new diver, or even a somewhat experienced diver could struggle to find them. ...A lot of this seems odd, the actions of the buddy do not.
It's a big sea of mostly black wetsuits, and if it weren't for different-colored/shaped fins, I'd be in a heap of trouble. And surely even the dive gods will admit to times--perhaps just seconds long--when your "lost" buddy is right above you.
I really don't like this "blame the victim" mentality--and I don't see how these people would not be considered victims of negligence and incompetence.