"What does it mean to be a good human being" is more general, so a probably a little less easy to answer. With "How to be a good man" you can cater to a smaller group. Women and men have different needs.
Some problems are specific to men or women exactly because our society has different expectations for men and women, so general advice good for one gender is not always good for the other. Example:
Q: How to be more appealing to the other sex?
A: Wear some light makeup and a nice dress.