I just found out why I have never known of an atheist eating dijon mustard. It is god mustard, atheist don't believe it exist.
city in the Burgundy region of eastern France, from Latin Divio, Divionis, from the personal name Divius "divine, godly," related to divus (see divine (adj.)). Noted for its mustard (Dijon mustard is attested in English by 1824).
Actually here is one atheist who prefers Dijon mustard to the English mustard most Brits prefer. All the better when it’s the whole grain variety. I have visited Dijon on many occasions and may actually have eaten it when I was there ...but I wouldn’t swear on that!