@FrippEnos
In nearly 20 years of teaching I have only ever known teachers refuse to deal with parents when those parents have been abusive to the members of staff. This does not make them "not good and/or reasonable" or "difficult" it makes them teachers that have been harassed, threatened, intimidated, verbally abused and in some case physically assaulted and that is a significant problem. (and this doesn't even touch on the pupils that are violent and abusive).
Actually, what I was saying was that most teachers are good/reasonable, but some are not. And those who are not are not like that because of anything which has happened to them. In my personal experience, those who I would term difficult do not refuse to deal with parents, they are difficult in other ways, manage situations and communication badly, etc. So we are talking about two different things here. i was giving the perspective of the average parent in relation to the few difficult teachers, and you gave the perspective of the teacher about difficult parents. (I agree, difficult parents will also cause a disproportionate amount of damage too)
In relation to difficult parents I'd be really interested to know - what percentage of parents would you say are objectively abusive ie personal insults, swearing at teachers, violent? I mean, not an exact figure, just your perception?
Are you saying that teachers who have experienced abuse from some parents then refuse to deal with any parents in a cooperative way? I don't think you are, i am just checking.
You also post about toxic ideas and images, these do not originate in schools they come from pupils homes, and they are allowed to watch these by the parents and then pass them on to other pupils by phone etc.
They come from some pupil's homes. Probably not the majority of pupil's homes, though that will depend on area probably. Some parents do not buy their children smartphones and they monitor internet usage, and they then have to deal with the fall out of their child being exposed to horrific content at school. This is something schools need to put a stop to, whether the problem originated with some of the children or not, do you not agree?
With regard to child development research, which would you like schools to follow?
There is only one body of child development research, and it is longstanding and peer reviewed (no whims). If the head and SLT are switching around, it means they have no idea what the research says and how it should be implemented. Schools should be aware of the research and it should be part of teacher training.
You have posted about "inappropriate and constant petty punishment" these again come from the management of the school. Most teachers will adapt around them, but in the end teachers are paid to follow the policies of the school, getting abusive with the teachers will never solve this problem as it needs to be taken up with the HT and the governors.
I agree with you, where it is following policies. But there is discretion for teachers - parents will be aware of this as not all of their dc's teachers will issue sanctions to the same extent or in the same way for example.