No she wasn't missing anything 'deliberatly'.
She was saying if she has to work on their birthday, her children's present are there for them if they wish to open them. Or they can wait and celebrate when they are there together as a family.
My father worked many Christmas's when I was a child. And we were given the choice to open our presents and celebrate on the day or wait for a day or two later when we could all celebrate together. As little kids we couldn't care less he wasn't there, his absence wasn't going stop us opening our presents (and actually we still got to celebrate when he was back). When we got older we chose to wait.
Most kids are actually mature enough to accept and understand that.
She is said that her diary is booked well in advance, she purposely is not at home on her children's birthday, they don't even get a card from her or a phone call to wish them a happy birthday, it gets ignored until the time when she will pay attention. Her son is four but has to make the " grown up choice" between opening his presents in a room alone or waiting. He will get a party shared with his sisters and his mother will not be there either because she misses birthday parties. She already missed sport's day and other school events because she finds work more interesting.
She says that giving birth is unemotional and therefore her child's birth unimportant to her. She is well off and is able to choose her time, especially if most of her work seems to be tv interviews. Not the same as you Father, who no doubt loved you and did everything for his kids, and thought time with you was precious too. Not an inconvienice.
Many parents have to work over Christmas, they are doctors, nurses, policemen but they do not ignore their children by being at work. People in Afghanistan at Christmas or on birthdays would give anything to see their children on those days. Katie chooses to miss those precious days, she choose who her children can have as friends by their name and she chooses to let nannies replace her at events that maybe important to her children.