"One thing you really have to watch as a writer is getting on a soapbox or pulpit about anything. You don't want to alienate readers"

John Grisham is warning authors to be cautious about revealing their viewpoints too strongly in their writing. He is suggesting that writers must prevent taking a strong position on any particular issue, as this could alienate readers. By push away, he indicates that readers may disagree with the author's opinion and resent it, thus disliking the writing. Grisham is suggesting that writers should be more subtle in their approach, and not be too preachy or judgemental. He is also suggesting that writers ought to understand their audience and the prospective responses to their writing. Eventually, Grisham is encouraging writers to be mindful of their opinions and how they are expressed in their writing, as this could have a negative influence on their readers.