I don't know how the movie can show exactly what the parents and the boy went thru.
And that's the reason when there are somebody annoyed me, I would rather look for a reason why people behaved that way. I still get annoyed. I am no saint but I am better at keeping my mouth shut and think about it.
When my son was a little kid, we hardly went out for dinner ourselves. But being Chinese with big extended families, there were many occasions that we had to go dinner with my mom and my siblings families in restaurants. It's really hard.
My oldest godchild was a tantrum thrower. She didn't have ad/hd, but she got emotionally overloaded and couldn't cope. Now I was her godmother and thought everything she did was adorable -- even the tantrums, but it was not quite so easy for her mother.
One time she was in the store with both her and her younger daughter who was a toddler at the time, and Julia had a tantrum. Honestly, her mother would have given her anything she wanted to shut her up, but what she wanted was not available.
Poor woman was just happy to get out of the store and into the car where the child could tantrum in private, and thankful the store was out of her neighborhood.
Then sometime later she met a woman who had seen her in the store that day and mentioned the incident.