The words "wholesome writing" might deter some folks who are only looking to be amused by things that are not necessarily good. But writing can be genuinely interesting, entertaining, and fun, while remaining wholesome at the same time but without being what is considered "preachy."
For example, I absolutely love mysteries. So many of them however are twisted, weird, or just depressing. So why can't they be lighthearted and uplifting? Why can't the books we read be clear of all offensive content and enjoyable for any age range?
Writers have a tremendous responsibility. You can either make someone a better person for having read your creation or a worse person. Every little thing matters. The simplest sentence can have a powerful impact on a person. This means that writers have the beautiful ability of touching hearts and making someone see something in another light.
Stories of heroes are what encourage us in our own lives. Fiction can only encourage us to a certain extent and the stories that are true resonate even deeper. But beneath the fiction of a narrative are messages and themes that apply to our day to day life and inspire us to go forward. Writers can never forget that more important than their stories are the people who read them.
Let's make our writing wholesome in the sense that when readers walk away from our books, they are better and happier people--ready to face troubles in their lives with courage.