What do you think a non believer would or should say about this?
If Jesus had said; "Wear masks in praise of me." You couldn't stop them from wearing masks 24/7. So someone needs to go through the bible and find some obscure passage that could be interpreted as a mandate to wear masks.
I'm sure there's something in there -- there always is.
I'd say to them, "Okay, so YOU want your Religious Liberties then build a compound that completely encloses your church/temple or what ever, make it a solid wall only accessible via a secure gate system with a coded entry system that is ENTRY only, assemble EVERYONE from your congregation INSIDE and seal yourselves in PERMANENTLY.
And when Covid spread through the congregation/s DO NOT call the Emergency Services,etc, just kneel down and Pray for a cure to be sent by God or Jesus BUT make sure you have a large enough area available to bury the dead."