Why do you need to consider the audience and the author purpose when analyzing a text

To understand the context of the text.

Explanation:

When analyzing the text, you have to keep in mind the author and audience to relate the text and understand the context in a better way.

For e. g. If a woman is cheated several times, she might curse men and say all of them are evils. However, if we consider the state of her mind, we can easily understand the context that because she was cheated and hurt, she is cursing them. She is referring to the cheaters when she says "ALL of them are evils". Those men who are decent and faithful do not relate to this sentence.