Opinions Please.....

I would hope an adult has the discretion to know that the other diners in a real nice place do not want to hear someone take a stand for their religion. There is a time and place for everything.
It could be I misread the situation, but I was having a conversation with friends, at the same table
Then I noticed the rest of the tables listening in...eavedropping, whatever you want to call it
So I just spoke a little louder to make if easier for everyone listening in to hear
When my kids were little and we went out for dinner, if they acted up they got one warning. Next time, they were told we all would be leaving and not be going out to dinner again until their Birthday,if they were lucky.

We only had to walk out once......in all those years.LOL

Simple parenting 101.....
Parents these days need to learn how to be creative. AND ACTUALLY CARE.

Just be sure as a parent you are ready to carry out whatever threat you make, because they will call you on it...at least the first few times