The bulk of the fighting is done by them?
LOL! - Aside from inter-tribal warfare with the so called Northern Alliance, they didn't lift a finger until we defeated the Taliban, basically ran them out of Afghanistan, stationed NATO forces, invaded Iraq, destroyed Fallujah, and kept 150,000 heavily armed and supported troops in Iraq.
In Iraq, we trained, armed and support the new Iraqi army, who should now do the bulk of fighting, don't you think?
The better question might be:
why are the islamists attacking fellow muslims?
Perhaps the apologists for common muslim behavior should answer that.