In the beginning when the game starts and snake starts about talking how everything has changed, the war, control of it on different levels, and the reason why people fight. There is no idealogy or countries behind that, just the war economy.
this last topic, the reason, why made me think that unlike the previous Foxhound, Dead Cell and Cobra unit these woman didnt really had a reason to fight and the BB unit werent even fighters or soldiers to begin with. They were victims.
like everything else they were made like soldier units and controlled (nano machines etc).
I thought for the theme that MGS4 is, they were fitting as completely "character-less" killing drones. I didnt expect them to be talky-talky like the other ones cause in their shell they are just that, mindless killing machines without any personality. Vicitms of war put in a shell to serve the war.
Untill ofcourse you get them out of their shell and they reveal their "real" uncontrolled state, a psychological wreck that can only walk towards you and try to hug you in need of love? Again also in this state i dont see them being able to have a conversation with Snake and they shouldnt, that would weaken them as they now are portrayed as emotional wrecks any talking or normal conversation would break that illusion.
Snake's response in why he should care about them, like previous poster is fitting, as Snake, like us didnt see them as living people anymore either.
Just emotional wrecks controlled by others...character less
So to get some BG info about them it had to come through a different person, enter Drebin.
my conclusion, this is done deliberatelly (ofcourse) in order to stick to the theme and to make it feel different like before MGS'ses.
..war has changed..its not what Snake and you the player are used to(or expecting). These girls are supposed to be character devoid killing drones.