Is it actually self-flagellation? A less dramatic description would be "introspection." You could also replace "agonize" with "think about," etc.

I think it's healthy to explore these thoughts, as long as it doesn't consume you. The trouble with a blog post is that you necessarily come off as heavily invested in the topic you're writing about, but it is also possible that he just wanted to be provocative and spark a discussion. It didn't seem as negative to me as some comments have indicated.