I find them cliquish and bitchy and not especially pleasant and a quick hi and bye does me fine. And some days I don’t even do that.
This is such a ridiculous statement. Do all women, on having children in primary school, suddenly become "cliquish and bitchy"? Of course not.
The reality is that at school, the only thing you have in common with most of these people is that your children are a similar age. That's it. If you're lucky, like in any activity where you're thrown together with a group of strangers, you hope to find enough in common to be friends. But unlike a hobby, or even a work situation, the similarity here is about as vague as it's possible to be - you have children, you live in the same rough area. That's not much to use as a kickstart to friendship.
Admittedly, there are some women who do seem to define themselves by the fact that they have children of a certain age at a certain school and they might then create little groups that are all obsessed with their children and the school... but those are people who I wouldn't want to be friends with anyway!
Expecting to be all warm and fuzzy with potentially 30-120 other families just because your children are at school together is ridiculous.