My MIL says it (not so much my FIL). Both are Jews.
My spouse does it also (also Jewish, though not practicing).
Moon Unit (my 11 year old daughter) says it!
And so do I sometimes also (I’m a complete shicksa). Iin daughter’s case and mine, it’s from hearing it from the in-laws.
I always figured he was saying “oi!” (British for “hey!” with an implied “wtf?”; as in, “Oi! You’re knicking my beer!”) and not “oy.”
I live in Texas now, but grew up in New York City, ann heard it all the time, from both Jews and Gentiles.
After a while, almost all New Yorkers embrace certain Yiddishisms.