The point that I am trying to make, is that Spock, by his own admission, told Burnham that he was fully aware that her language towards him was not meant, that it was done purely to hurt him at that moment in order that she could make her flight away from the family home, thinking she would never return.
He knew this as a child, it hurt him at the time, but he still KNEW it wasn't meant to be taken at face value.
So therefore, why would his logical mind. his developed adult mind, give any credence or feel any anger towards Burnham ?
I'm not trying to belittle the emotions of people on here who have had traumatic experiences in childhood, nor make light of such experiences.
The reality here, in the writing, in the dialogue, is that Spock knew Burnham, while using totally callous language, wasn't sincere in what she said.