I actually agree with Katie on this one. It's not always possible to have a birthday party on the exact day. She clearly loves her kids very much, but just gives them a party on the weekend where it can be celebrated as a family, together.
The other woman came across as a bit hypocritical to me. Going on about how children's birthday's should be celebrated on the day, when actually, she did send one away to boarding school and I bet she hasn't seen them on their birthday.
Why does sending her child to boarding school make her a bad parent? Maybe they have scrimped and saved and sacrificed to give their child the best education possible. We don't know.
Having nannies attend your children's sports days, telling your children who they can be friends with, based on name, giving them a shared party every other year, plus all of the other nonsense she's come out with, IMO is worse than sending your child to boarding school.