CAIR seems to be concerned about the fact that a counter terrorist exercise was carried out in a mosque. The CAIR people say, "The use of a fake 'mosque' in this type of drill sends the wrong message to law enforcement officials who may now view mainstream institutions, such as Islamic houses of worship, as potential security threats," said Ahmed Rehab, executive director of CAIR's Chicago chapter (CAIR-Chicago). "Officials must be trained in dealing with hostage-taking and responding to chemical, biological or bomb attacks. We are only questioning the wisdom of linking the American Muslim community and its institutions to such incidents."
I can only assume that these people are living in cloud cookoo land. Because mosques ARE unfortunately very attractive to terrorists, almost every other month, you can find terrorists holing up in mosques. And this is in so many countries. So it is indeed not surprising that this happens. See my previous essay here. You cannot really blame counter terrorism people to think that this can indeed happen in USA or UK? And interestingly enough, have they ever said anything about terrorists occupying mosques? I couldn't find anything. You see, the public at large might not understand the significance, but anybody who has followed terrorism will know exactly why CAIR are doing and saying so and the reasons are not really very pretty or attractive or even reasonable.