There have been attempts by some government officials to tax churches before, even though they’ve not been taxed since the foundation of this country. And the US Supreme Court has said (at least in one case) that this power to tax would also mean that it would be the power to dissolve the church, too ... and therefore to tax it would be Unconstitutional.
What was meant was, and they said this ... was that if the taxes were not paid, the power to tax also gives the power to seize and sell, thereby dissolving the church ... therefore the power to tax is Unconstituonal, per the First Amendment.
Again: “ Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof”. The RIOT Act neither establishes any religion, nor does it prohibit the free exercise of any religion.
It simply indicates that Islam is not to be recognized as exempt from taxation due to the fact that it is a political institution in conflict with the guaranteed principles of this country.
Note it is a POLITICAL institution and not a religious one.