Why don't you know that by the way?
How could I know the reason why I don't know that?
How should they even know how to answer a question with another question?
Wait, why could they not know how to do that?
Is a possible that they referred to some manual?
You mean, like that stupid manual that, forty years ago, made me commit millions of neurons to the task of policing my fingers to make sure that they used the Oxford comma when writing in English, but avoided it when writing in Portuguese, not knowing that I could have just omitted it all the time and be just as correct?