Since he looked at your chevron and thought private, I'm guessing he was Army. He probably did his tour and got out as soon as he hit stateside. He was probably having a bad day of his own and took it out on you. That can happen at any age but tends to happen more and more as you get older.

I'd say forget about it; he was being a dick (which may or may not be a permanent condition for him) but you have a beautiful family and formal paperwork filed with the state now. Just remember him and try not to BE him in 40 years ...