The OP has stated that the Father wasn't shouting.
As a former CP SW (I have a long posting history, but haven't been on the board in a while), I will point out that, as people, we vary.
So our level of general "aggression" can seem more than another persons, as can other mannerisms etc. so it is impossible to judge from one incident, what the family situation/dynamics are.
In short, we all grow up in our own family, environment, area and this means that the world is populated by different personality types etc.
I live/work in a rough part of Merseyside, how people live/speak etc would be shocking to many.
The parenting isn't ideal, I have run Parenting courses, but it isn't abusive, as such.
There are a lot of people who accept that whilst their upbringing wasn't ideal, their Parents, didn't have better strategies for handling bad behaviour and a eight year old causing unneccasary damage to a pair of shoes (which may not be easily afforded) is bad behaviour.
As someone who used to come into contact with abused children daily, it's telling that the girl stuck her leg out, after the brother was chastised, that isn't usual behaviour from a child with a parent that is feared. It was a "winding up" act.
I agree that I've heard much worse emotional abuse/blackmail being used, that wouldn't probably hit most peoples/posters radar, weekly, on my travels.
The effects of which are deeper and less easy recoverable than being rough handled slightly more than what is ideal.