If a fiction writer aims to persuade, why might it be important to inspire sympathy or empathy for a character?

It's important for the reader to feel sorry for the main character that the reader will accept the author's point of view.

If a reader sympathizes or identifies with a character, then the effect of events on the character will have more meaning and impact.

If a reader identifies with a character, then the reader will believe anything that the character says.

An author's opinions will be more persuasive to the reader if the reader feels that the author has the same kind of background.