Hey, at least the Christians gave you words to blurt out when you're pissed, eh? I mean, what's a real atheist gonna blurt out? Nothing? And for the record, I refer to those fish thingies on bumper lids as "Holy Mackerel". See? We even have a sense of humor."*******" is an exclamation in common vernacular in English. It does not imply belief in a deity. Your teacher was/is an idiot. So if I roll my eyes and say "Jesus Christ!" at his nonsense, it's not exactly a prayer.
What's next? "Holy ****" as a proclamation of faith?