I had a similar experience a few days ago. As I don't own a kilt yet, I rented one and wore it to a Scottish dinner at the church where there are quite a few scottish ex-pats. One of them commented that I had a "Real" kilt. She went on to say that it had the deep pleats.
Perhaps your detractor felt the pleats weren't deep enough? Another possibility is that "Real" kilts have a 2" rise above the belt line.
I'm just guessing at this, so don't take it as gospel.

Uncle Ricky