a) The author might disagree with my asessment. A pull request would imply that I consider it an error, but I think it's more a question of style.

b) I already waste too much time on HN. Forking a project, trying to understand all of it, making changes, writing a pull request, etc. would probably take me all day but I need to clean the kitchen and take care of the kids and work on some overdue client work that I have been postponing for far too long.