How much writing to most of us do? Very little I suspect,The simple fact is that, although everyone learns to write,
few of us ever do. We text, we email, we go on twitter and the resst - and how ro we import information - we type it.
This applies even more to school children who do all their work online. Unlike us, when they come to exams they do not have 10 years of writing longhand essays behind them. So it is hardly surprising they find writing exam papers hard work. As I remember one exam paper, 3 essays could require 15-20 sides of A4 written in three hours.
It is like asking someone who swims 40 lengths a day in the local pool to go our and swim the channel without extra training.
As someone with almost unreadable writing I have a lot of sympathy with this. Even in the Sixth Form, teachers were trying to improve my writing. I now know that I am dyspraxic, but in my day even dyslexia was unheard of.
DS also has dyspraxia, so for us two being able to type our exam papers would have been bliss.