The word comes from Judaism. During mass reconciliation the rabbi would bring a goat to the alter. The sins of the people would be absorbed into the goat, and it would then be killed, its' blood staining the alter until cleansed. This is what Jesus Christ reflected in his crucifixion, being a scapegoat.
(v.) to make the scapegoat
To be a scapegoat is to take heat.
Scapegoat was often burned, but sometimes the poor stole it and ate it.
When parents are too lazy to raise their kids and blame videogames, rap music, etc. to hide the fact that they have poor parenting skills