The city is being sued on these grounds by Catholics and Hasidic Jews for restricting their constitutional right to freedom of assembly.
Perhaps you are referring to the UK, but that’s not accurate as far as US laws are concerned. The religiousness of the event is not what requires permission, it’s the fact that large numbers of people will be in attendance in a public setting and are planning to move along public thoroughfares to another location. The event will potentially block roads and sidewalks, restrict normal pedestrian and vehicle traffic, prevent freedom of movement to and from homes and businesses, etc. It is for those reasons that fire marshals, ambulances and police resources need to be on standby, which triggers the permit process.
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