Al-Qaeda seeks to combat the idea that people of different religions can live harmoniously together in the same society. The anti-mosqueteers are certainly doing their best to combat this idea as well.
Al-Qaeda seeks to subordinate private property rights to religious law. This is exactly what the anti-mosqueteers do when they declare other peoples property sacred ground and propose on this basis to interfere with their peaceful use of it.
Al-Qaeda seeks to position itself as the representative of the entire Muslim community. The whole anti-mosqueteer position makes sense only on the assumption that they support al-Qaedas claim on this point since otherwise banning an Islamic cultural center because the 9/11 highjackers were Muslim would be no more salient than banning a YMCA because the highjackers were male. (A young woman said to me: I have had the most horrible experiences with furriers; they robbed me, they burned the fur I entrusted to them. Well, they were all Jews. But why did she choose to hate Jews rather than furriers? Jean-Paul Sartre, Anti-Semite and Jew.)
Al-Qaeda employs a double standard, condemning its enemies for killing innocents but excusing its own similar actions. This approach too gets its stamp of approval from the anti-mosqueteers, who express far more concern about what might be built near the site of the 9/11 bombings than about what might be built near the sites of American bombings of Muslims.
Al-Qaeda seeks to intimidate its opponents into appeasing its irrational demands. What are the anti-mosqueteers doing if not endorsing this tactic when they suggest that the Islamic Center should cave in and compromise out of concern for the anti-mosqueteeers feelings, regardless of the merits of those feelings? (Likewise, why couldnt southern blacks compromise with the KKK? Sure, maybe legally the blacks were in the right, but the KKKs bigoted feelings were strong and sincere and deserved respect, no?)
Im not saying that the anti-mosqueteers are literally in the pay of al-Qaeda. But they might as well be.