By using his real name, readers who know that name can get more out of the article. Imagine if he is actually a state senator, or a minor celebrity. The reporter here isn't doing the difficult calculus of "does revealing his name do more good than harm" but is instead relying on company policy. Alternatively the reporter has done the calculus and are using policy as a shield. "Nothing personal, it's just business"
Let's change the setting to Weimar Germany, and the subject is a prominent Jewish blogger. Still think it's ok to expose his real identity? "Just business"?
