Danahar here is using the discredited logic of the Goldstone Report, which tried mightily to distinguish Hamas from the Al Qassam Brigades, not acknowledging that at least three quarters of Hamas policemen also were Al Qassam terrorists.
Notwithstanding that the BBC itself admitted that this wasn't true only seven minutes later, it is absurd to claim that Hamas has a "political wing." There is really no distinction between Mahmoud Zahar and the Al Qassam Brigades.
And for proof, you only need to look at these photos taken within the past two days of Mahmoud Zahar himself:
Political leaders do not dress in military fatigues and carry submachine guns.
In the speech Zahar gave at this Qassam Brigades rally he emphasized that Hamas "will harness these missiles to serve the Palestinian cause and liberate the land," meaning destroy Israel militarily. He also said that the Palestinian people are patient and steadfast Mujahideen, or jihadists.
He looks and sounds pretty military to me!
(h/t Israellycool, Yoel)