Most of the people the Romans were up against simply didn't who they were dealing with.
You couldn't pick up a book in Ancient Britain about the size of the ROman Empire, its operating techniques, etc.
She was out to revenge an unspeakable and stupid outrage against herself and her people.
If I remember correctly, Paulinus was later recalled and the Romans tried to be more conciliatory instead of predatory.
Indeed...good points to bear in mind. Thanks.