I used to have a HUGE problem with unbelievers saying, “Oh my god!”. But after thinking about it, I’ve changed my mind about it and the key lies in the word “my” and the lower case “g”. Here’s why.
Unbelievers have, whether they know it or not, in their mind a concept of a god that they have created that suits them. An idol if you will. That god is no more real than Peter Pan. That god is the one they will “go to” when they die, the one they pray to when they need something, and the one that gives them warm fuzzies when they see fireworks on the fourth of July. And like any made up god, he isn’t real. So for them to say “Oh my god“, they are blaspheming their idol god instead of the one Triune God. It’s actually kind of funny if you think of it that way…you just need to retrain your ear to it. All bets are off though when an unbeliever uses the Lord Jesus’ name in a blasphemous fashion. THAT’S a whole different paint job!
That being said, nothing burns my butt more than when a believer says it. It’s blasphemy. It’s using His name in a vain, irreverent, loose, disrespectful manner. It speaks volumes on how holy and precious God is to them. If you have a pearl of great price, you don’t tie it to your bumper and drag it through the mud.