I’m sorry that the other person didn’t help
It was to basically destroy everything the south had, they would do it because it would leave the south short handed on supplies such as food, water, etc
To remove preconceived notions and ideas from one's mind before writing is to be unprejudiced.
If you don't have any prejudice towards the topic you are talking about, means to be completely objective and not to show any personal feelings about the said topic.