While this is true, correlation is not causation and just as there are a lot more ordinary people in this country than terrorists (unless you believe the Bushite propaganda), there's probably a lot more ordinary people who dig the Constitution than domestic terrorists.
I don't keep a pocket copy of it on me or anything but I do firmly believe that a well thought out understanding of the Constitution is essential for being a citizen (that goes for other countries, too, with their respective government-establishing documents). It's important to know your rights as well as to know what's expected of you where you live. Your taxes pay for the government, so it's handy to know a little about it.
The real thing that I take issue with here is that mere possession of /any/ readily-available document could be grounds for suspicion. Implicit in our first amendment rights is the right also to consume whatever speech or press we wish. Like the Patriot Act's provision that libraries could spy on what you read. If a book is in a public library, it should be understood that I can pick it up and read it without suspicion.
It may take a little longer than four years to dismantle all the horribly horribly wrong things that have been done in the name of national security in this country.