Which tune?
Another case of the folk process; I learned Angelina Baker, the one that seems to show up most regularly at sessions and had no problem with it. Then I heard another version which I believe is nearer to or possibly the original song by Stephen Foster (who was not Irish). I now sometimes have trouble getting one version out of my mind when attempting to sing the other.

I think you are probably correct in your assumption that someone believes that any fiddle tune must be Irish. But then doesn't every fiddle tune sound the same to the uninitiated.

Hoot