Exactly. The motivation should be moot.
Those people pay taxes too. They should be allowed the use of public facilities to meet, just as they can ride the train, or the bus, or whatever.
The fact that the Constitution's authors thought that religious discrimination was an important enough problem to be addressed explicitly should not be turned around into an excuse for discrimination against all religions.
Regards,
-scott anderson
"Welcome to Rivendell, Mr. Anderson..."