Smudge - as BCG said - you have to live and work in Nigeria for a while to fully understand how utterly corrupt and venal every level of Nigerian society is. Everybody is only interested in themselves and will steal anything they can, and are continually on the look out for opportunities to scam each other.
Whenever there is a car-crash in Nigeria, passers-by flock around not to help the victims but just to loot them.
There is a culture of impunity that means that people in power are completely immune from prosecution. They will run people down in their large vehicle convoys and not even stop. Ministers will brazenly steal billions from their ministry, and there will be no pressure whatsoever for them to resign - simply because everybody else in power is also stealing as much as they can.
The military is no better - as I alluded in an earlier post, most equipment is procured at great expense just so that senior officers can extract huge kickbacks from the arms dealers (usually Israeli and Chinese since western manufacturers cannot pay kickbacks nowadays). The equipment is then just left to rot because there is not enough money to be made out of maintaining it.
The reason these girls were kidnapped in the first place is because the Nigerian soldiers who were supposed to guard them accepted a bribe from Boko Haram to run away.