True, the misunderstanding over bonfire night isn't make or break. It's a neat example, though.
Going back to your first paragraph, it sometimes bears repeating that children - by definition - do not have a mature understanding of adult issues. They don't even have comparators because their parents are the only ones they've had. Until somewhere around puberty, parents have an almost god-like status to their children. The parents feed, house and educate them, literally hold the power of life and death.
If a parent, for reasons of their own, is driven to strictly control a child's diet, say, or reacts to arguments by silent withdrawal (or any number of other behavioural glitches), the child will be affected and will have issues in adult life resulting from their childhood dependence on a maladjusted parent. It doesn't matter whether they understand what drove the parental behaviour - children can't really understand and cannot help them, and by adulthood the damage is already done.
But understanding it as an adult can help. It's true that everyone parents the best they know how: it's just that many parents are running on wonky programming by their own parents. Understanding it can help an adult to reprogram themselves, difficult as this always is. But it won't help to repair the relationship if the parent refuses to accept that their program is wonky! They'll just keep outputting the wrong messages on repeat, as they always have. For the adult child striving to rebuild themselves as a better-functioning human, this can be intolerable. A parent's words still cut deep, and what do you do with a mother who keeps calling you fat, for instance?
I ended up taking the piss out of my mum - gently but with determination. It took twenty whole years. I honestly wouldn't blame anyone for deciding not to bother with her unless she cut out the weight comments. This can be extrapolated to any parental dysfunction, of course.
Oh, and she did apologise eventually. It was a slog. She's still diet-obsessed, but doesn't pass comment on mine.