Only when colonists tried to form a nation, and met with others who practiced different religions (or none, like Thomas Jefferson), did they put freedom of religion in the Bill of Rights.
Mr. Stossell has made an error and/or a lie of omission in his commentary. The first paragraph above is precisely the reason that the First Amendment uses the wording "CONGRESS shall make no law respecting establishment..." - the power to establish (or not) a state-sponsored religion (within the borders of an individual state) was left to the individual states.
PS - Expansion of the scope of the 14th Amendment has made the 1st amendment issue of individual states establishing a state religion a moot point.
You are correct that the First Amendment refers to Congress, and not to the states. Until relatively recently, many state constitutions still reserved the right to establish a given church within their borders.