The celebrant said it helps to calm the nerves and relaxes the brain after the day's stress.

This got me laughing. This is purely a mindset thing. Water can play this role if one believes it will. I used this line to justify my actions too when I was a consumer, 😂.

I didn't bother replying them any further because nothing can make them stop.

You did the best thing. No one can be convinced otherwise in that situation. You saved yourself the futile venture.