I would have had no problems with allowing that, so long as no laws were broken.
Either everyone has religious freedom, or no one does.
Bullhockey!
This has nothing to do with "religious freedom" although Muslims and the ACLU are trying hard to cloak it in these terms (and so are you, for that matter). In point of fact, if Islam prevails nobody except their adherents will have "religious freedom". The Infidels either convert or die (it is possible for a short interregnum of Dhimmitude).
Subversive organizations should not be allowed to propagate in this country and especially when we are in deadly armed conflict against their adherents. There is no necessity under our Constitution to cooperate with our own demise, even one cleverly cloaked with "religion". Islam is a complete system of culture, laws and government and not just a system of worship.
The overarching goal of Islam is to overtake and change the entire target entire culture (ours in this case), peacefully if possible but ultimately through force if necessary. They would institute Sharia Law in place of our Constitution. Such behavior meets the definition of a "subversive" organization and unAmerican activity.
Islam is antithetical to American values and Western civilization. This is a "survival" issue, not just a "religious" one.