Personally I think it's a stupid idea to worship in general, but within the context of a believer who believes that God blesses them for good actions and loves them, perhaps they feel like God will protect them. Or if they do die, they'll be rewarded handsomely for being true believers and dying as martyrs.

No we absolutely cannot. I prefer the American Convention on Human Rights, which states:

The right of peaceful assembly, without arms, is recognized. No restrictions may be placed not the exercise of this right other than those imposed in comformity with the law and necessary in a democratic society in the interest of national security, public safety or public order, or to protect public health or morals or the rights or freedoms of others.

Constitutionally protected rights aren't absolute though. And Churches are required to obey all sorts of laws already. Mundane the city can demand that a Church fix their leaking sewer lateral. And red tag their building if they don't.