Those particular ones were likely added quite awhile ago and came over in a merge. I don't know that family members adding lots of other family members is common practice.
In any case, the help page says more than four or five becomes unwieldly and that profiles managers can be removed but it should be discussed. So the Cape of Good Hope project leaders/coordinators should talk to the other PMs listed, particularly active ones, and see if they want to remain as a PM or move to the Trusted List. I'm sure the PM who added all her family members will understand about moving them to the Trusted List.
(Note: The ones who don't actual have active profiles may not be able to be removed right now. If I remember right, we aren't currently able to do that but I'll let Jamie know we need to look into that glitch at some point.)