I would start invoicing people for your time until you get a legal cease and desist. Then sue them, just because they accepted responsibility.

Make it cost them money.

The SCOTUS precedent

Don’t worry they don’t believe in Precedent anymore. You just need to grease their wheels. I hear it’s cheaper than you think.

You could counter with a Baha’i prayer. They are still an Abrahamic religion, and they have literally hundreds of prayers for practically every topic.

And you can’t disrupt the meeting by interrupting the prayer until they kick you out, because then presumably your employer would fire you, I assume? 'Cause if not, you should definitely ruin their motherfucking christofascist bullshit.