How do you explain the fact that the outrage over the abducted girls is mostly from the West?

Muhammad and his followers fought many battles. Some were offensive some were defensive. Following a victory the Muslims would take captives, or prisoners of war. Muhammad would usually distribute the captives, both male and female, as slaves to his soldiers. Islam provides some basic rights to its slaves but these rights are limited. Naturally, the rights or demands of the slave owner were greater than those of the slaves.
Female slaves were used for primarily for work. But they also provided another service to their male masters ....

FROM THE QURAN - 70:22-30
"Not so the worshippers, who are steadfast in prayer, who set aside a due portion of their wealth for the beggar and for the deprived, who truly believe in the Day of Reckoning and dread the punishment of their Lord (for none is secure from the punishment of their Lord); who restrain their carnal desire (save with their wives and their slave girls, for these are lawful to them: he that lusts after other than these is a transgressor..."