I'd heard that the exclamation "Oh my God" is considered offensive nowadays. Why is that? Isn't it just an exclamation?

Native speaker’s answer
Rebecca
The phrase "Oh my God" is offensive depending on who you talk to, but largely it's considered fine to say! If someone is religious, it could be considered offensive to them since it uses the word "God" in it. Like a type of blasphemy. So quite a few people replace "god" with "goodness" or "gosh" for a milder version of "god." Ex: Oh, goodness! I didn't see you there. = Oh, god! I didn't see you there. Ex: Oh my gosh. We've been waiting in this queue forever. = Oh my god. We've been waiting in this queue forever.