The Constitution does not protect organizations that call for the overthrow of the U.S. Gov’t.
CAIR does that IMHO, if not in legal opinion.
Sure it does. You have every right to join the Communist Party or other groups that advocate changing our form of government, as long as that advocacy does not involve illegal activities.
If you disagree, please point me to the relevant section of our Constitution detailing this exclusion from the Bill of Rights.