You'd be surprised to learn that every culture at the time (and much later) did animal sacrifices. Did you think the Ancient Greeks or Romans didn't sacrifice? The main crime Christians were convicted for in Rome was refusing to sacrifice to the pagan gods.

Singling out the OT is grasping at straws. If anything, God forbid idolatry and human sacrifices the Canaanites and other people brought to Baal/Moloch.