Publishers who use a WordPress commenting plugin can configure their WordPress settings to display all comments that their readers make in an article. 

This can be a tricky procedure as there's two fields in the Reading Settings page that can easily be confused. 

The Blog pages that show at most field is what needs to be modified to adjust the feed for reader comments and defines the number of comments to be displayed. The Syndication feeds show the most recent field however, is the article feed that defines how many articles should be displayed on the publication's home page. 

To increase the number of comments to be displayed for articles:

  1. In your WordPress account, click Settings → Reading in the side panel of your WordPress admin account. 
  2. In the Blog pages that show at most field, modify the number accordingly.