There are also Arab Christians. And white or black Muslims. The Christmas bomber was African.
In response to all, but particularly zombie:
I think it was unnecessary to jump all over Warbler. If we're talking about looking at historical trends, why is it racist for him to accuse Al Qaeda? I believe it is premature based on insufficient evidence, but it's certainly not racist. Al Qaeda is a terrorist group, not a religion, not a race. Several plots of theirs have been attempted since 9/11, and nearly all of them have been bombings, not mass shootings. I agree, Warbler is jumping the gun, but he certainly displayed no racism in doing so. He followed a historical trend.
Meanwhile, the home grown terrorism everyone is referring to has not been terrorist in nature. Terrorism is political, designed to evoke fear in enemies and political change as a result. Newtown, Aurora, Tucson, Lancaster...all of these were motivated not by a political agenda, not to effect change, but out of mental instability and/or anger. Even shooting Rep. Gabrielle Giffords was not a matter of terrorism because there was no political ideology Loughner was pushing, but he simply had disagreements with Gabby and wanted to kill a bunch of people because he was unstable. And for what it's worth, he was very liberal.
Would it have been anti-Irish or anti-Catholic for the Brits to jump to the conclusion that a bombing in Manchester in 1996 was committed by the IRA? Give Warbler a break.