To think it's not the job of teachers...

[Sidalee7]

To show children how to behave?

I was in a cafe earler where at the table next to me there was a 4 year old girl, her dad and her granny. She was being a bit whiney, nothing major but they were talking about how difficult she was (in front of her) and then the dad said "When she starts school it will improve as the teachers will show her how to behave".

AIBU to think this is the parents job - not the teachers?

The fact that teachers and nurseries both say that the number of children who do not have basic skills when starting school is increasing, certainly shows that something is going wrong.
And children have started school at 4 for many decades. I am middle aged and started school at 4 and a half, and I was not the youngest. And in those days we did sit behind desks and listen to the teachers.

It's the job of teachers to try and help to raise and educate children into being decent human beings, as well as all the curriculum stuff.
Way back in the mists of time when I was shiny and new at the teaching gme, it was called 'The Hidden Curriculum'
Yes, it would be nice if parents were the key facilitators in this, but many are not. Even if they are fantastic, sometimes it takes a while for children to mix and mingle and find out that not everyone lives the same life as them, has the same values or the same life chances. Learning tolerance and patience is easy if everyone around you is tolerant and patient. More of a challenge if they aren't.
That's why EY/FS is the most important year in a primary IMO.