Concern is that Big Brother Complex is being confused with girls who like older men (ie a big brother figure)

Propose:

Big Brother Instinct for what is currently Big Brother Complex, men who like protecting those weaker (and usually younger) than themselves- ie: "Acting like a big brother"

Big Brother Attraction for girls who like older "big brother" type love interests.

Big Brother Is Watching covers government as Big Brother.

Big brother instinct sounds better. For one thing "Complex" implies a rather smothering version. But many perhaps most of the examples given are heroic versions and instinct would cover both a healthy protectiveness and a smothering one.

Change it to Big Brother Instinct