There are two types of articles that belong here on HN. The first type includes articles that speak for themselves. Everyone learns from them, but fell little need to comment unless they have something small to chime in. This type should have a low ratio of comments to upvotes.

However, the other type includes articles that provoke people and cause discussion. It doesn't just include contributing comments, but rather it contains debates and opposing opinions. These types of articles need a balance between a low and high ratio. However, the religious arguments you speak of are usually easy to find. These arguments are usually found in a deeply nested comment thread. Once you discard of fourth level comments and all the noise below, you should find that the ratio of comments is a pretty good signifier of the quality of the article.