Because the mullet is “un-Islamic.”

Via JPost:

The Hamas authorities in the Gaza Strip have begun arresting young men with “immodest” haircuts, a Palestinian human rights group complained Sunday.

The Palestinian Center for Human Rights said that Hamas policemen arrested several young men and cut their hair. Some of the men were beaten while in detention, the group said.

The group called for an investigation into the assaults, saying they harmed personal freedoms.

According to the group, Hamas policemen stopped over the past few days several young men as they were walking in the street in various parts of the Gaza Strip.

The men were taken to Hamas police stations under the pretext that their haircuts were immodest.

“The men had their hair cut in a humiliating manner and some were beaten,” the human rights groups said.

The men were released only after they signed a document pledging not to appear in Western-style haircuts or wear low-waist pants.