The threat to US (and Israel) hegemony comes from masses of Muslims in Africa, Central Asia, Afghanistan, Iran, Pakistan, Bangladesh, South East Asia, not from the Arabs who are weak and under US control.
The best way to eliminate this this threat is to keep the Muslims weak, poor, illiterate and powerless by fermenting sectarians divisions within their societies like in Iraq, so that the Muslims keep on fighting among themselves and remain weak for ever.
Islamic militancy, terrorism, fundamentalism and extremism are their keys and the Talabans Al-Qaeda and people like Musharaff are their tools.
This is the reason why there is enemity between the militants and the Pak army and cause for this killing.