To think this is potentially harmful?

[zudoyne]

If your KS1 aged child seemed to be struggling, making them sit down and complete work after school when they and you are tired and tempers end up stretched, parents end up shouting and punching tables in frustration, child is sobbing and petrified of homework or getting things ‘wrong’

How would you let the parents know that their actions are misguided?

It depends on what my relationship to the parent is. If I'm the child's teacher, I'd request a conversation with them about the amount of extra work the child does or doesn't need, and that too much pressure is counter productive.
If I'm the spouse of the parent, then I'd be calmly pointing out the error of their ways before insisting that things change immediately. I'd also be spending lots of time with the child to see if the damage can be undone.
If I'm a neighbour, hmmm, I don't know.

Unless you are the child'd teacher or parent, I would stay out of it.

I’m not surprised that the child is petrified of getting anything wrong if the parents are punching tables and shouting.

That’s awful behaviour from the parents.

Someone needs to sit the parents down and ask how they would react in a situation where they were trying to learn something new and were shouted at and saw aggressive behaviour from people who are likely three times bigger than themselves.

I used to have this happen to me. If I said 'I don't know' I'd get shouted at and berated.

I still have confidence issues now.

Someone needs to sit the parents down and ask how they would react in a situation where they were trying to learn something new and were shouted at and saw aggressive behaviour from people who are likely three times bigger than themselves

This^^. Ridiculous behaviour from the adults.

I most certainly would try to advocate on behalf of the child. I’d try not to be critical but I would attempt to offer practical support/advice. Poor child. School is such bullshit and it’s tragic when parents use it as a yardstick to best their kids.

I have never understood how parents can get so angry they're literally being violent to inanimate objects... of course that is harmful!