"Oh, are you autistic like he is?"
Likely met with bewilderment or denial. Followed by my,
"Well I see that I've upset you. I'm used to that with his autism. My son doesn't have good social skills, gets frustrated and angry easily and often says whatever is on his mind without thinking. It's so embarrassing when he's rude like that. I just assumed you must be autistic too since you look just like he does when he's having a tantrum. My mistake - you must just be a miserable judgemental person instead. I hope you can get some therapy. Good luck with that."
This may give them something to think about...or not. If nothing else, their anger will focus on me and not my beautiful son. I'll feel better to model strength for my children.
I realize that we'll have our meal interrupted when my son gets too out of hand. I can't remember when a family meal has lasted until dessert, when we'd each pass a spoonful of some luscious chocolate sweetness and lingered over coffee and conversation. Instead, our family is prepared for quick exits. We've done this brisk retreat countless times and have a battle plan prepared. I bark out orders like a general: "You - flag down our server for the bill and some takeout boxes, you - find cash because we can't wait for a charge transaction, you - grab the backpack, you - grab my purse, you - please carry him and take off his shoes so his kicks don't hurt. Pull up to the door, I'll fill the takeout boxes, handle the bill and meet the car. You - put on his movie in the car, give him his toy, buckle him up and really try not to touch him or yell." This only gets more complex, louder when I don't have my husband with me for backup.
I vow on our silent, exhausted drive home to never, never, NEVER go out again, it just isn't worth it. So with or without a rude interaction with others, we'll go through our own private war regardless. Hopefully we'll have enough energy or appetite to heat up our meals at home and sit chewing in silence.