[The Syrian Observatory for Human Rights] said ISIL had executed the eight men in Aleppo province for belonging to more moderate groups. The men were crucified in the town square of Deir Hafer in eastern Aleppo and would be left there for three days, it said.
...their corpses were still on view
What is the motivation for these excruciating executions?
The men were accused of being "Sahwa" fighters, the Observatory said, a term ISIL uses to refer to rival combatants whom it accuses of being controlled by Western powers.
Or "because they were considered too moderate", in Reuters' paraphrase.
ISIS has been practicing this:
ISIL also crucified another man in the province in al-Bab town near the Turkish border, [The Syrian Observatory for Human Rights] said. He was pinned up for eight hours as a punishment for giving false testimony but survived the ordeal, the Observatory said.
ISIS/L is apparently taking its horror campaign very seriously.