Including the word "crazies" is probably counter productive to your argument as it puts the other person on the defensive. You will be better served by keeping the other person away from becoming defensive.

You may want to have your evidence that prayer is usually more harmful than not praying. Personally I am not familiar with that evidence. I have seen evidence disputing efficacy of praying, but not any stating that it may in fact be harmful.

The argument that it is in fact harmful would presuppose sine higher power monitoring such prayers and actively working against you. This is a stretch even for the most extreme crazy.

It may also help your case to have an alternative response to the interruption that your sneeze creates. Seinfeld noted that the typical responses to the sneeze was not necessarily to plead for the favor of an all powerful deity but to make the initiator of the sneeze which created the interruption feel better about themselves.

To that end, Elaine suggested responding with "You're so good looking"

Depending on your environment this may or may not work. Many of us have to worry about sexual harassment claims.

Especially in a tech environment, it may be more appropriate to respond with "You are so smart" or perhaps respond in leet Y0u 4r3 50 5m4r7

This is something really funny. You really have a unique idea there. - Mark Zokle