Earlier today, someone posted about a child ‘misbehaving’ in a store, the poster wanted to go up and give the parent a lecture on ‘parenting’.

I had to ask myself, “Are you sure? Do you have the answers? Are you qualified to make this judgment?”

I was not present, so I do not know.
As I read the post, much of what was described sounded like an autism ‘meltdown’.  In a crowded store, lots of lights, sounds and people, sometimes only being touched in passing, many autistic children  scream or become physically violent in order to cope with a situation they cannot react to in the way others do.
No, the parent did not react as you felt they should have. Had they removed the child or given your suggested  ‘good whooping’ that might well have exacerbated an already upsetting situation.
Autism doesn’t manifest with spots, rashes or missing parts… it is an overwhelming neurological condition and effects the child, family and caregivers. A parent has to learn what works and they can only do so much.
Maybe not, but sometimes our attitude only adds fuel to an unquenchable flame.  It was probably best, you walked on and only raved on FB this morning.
I live with someone with autism, when he was small, this ‘inappropriate behavior’ was one of the things we had to deal with frequently.
He has learned and progressed, we have learned and progressed. Crowds and lots of noise still make him ‘melt’. It’s easier now to refocus or leave, but there are times when you just have to bite the bullet and do your best.

And we try, every day has a challenge, some very small, some groundbreaking, some earth-shaking. We win some and we lose some, but we keep on.