It's not at all. It's the un-PC-ness of it all that has the libs all indignant. They're upset because it was done to mosques but not to churches and synagogues.
I think the reference to 150 sites, balanced against the statement of checking out hundreds of places per day, suggests they divied Northern Virginia up into search areas, and then checked EVERYTHING and EVERYBODY.
BTW, we had several federal police patrolling my immediate neighborhood night and day for several months after 9/11. The problem was the AlQaida ground support team lived in a nearby townhouse development. They disappeared 9/11, taking their taxicabs with them into the dark of night. However, many left dependents behind, and who knew if all of them had left.
Fairfax Police pulled the "bicycle patrol" in the face of the fact that there was some serious fire power rolling around. We haven't gotten them back yet, so the risk is still here.