I really don't understand this article's high tendency to slip in tangents that have little to do - long sentences enclosed by brackets, or worse, hyphens which

I really don't understand this article's high tendency to slip in tangents that have little to do - long sentences enclosed by brackets, or worse, hyphens which made side stories hard to distinguish from main story. Those things have so little to do with the actual subject of review and serve little purpose. Perhaps they're there to show off the author's knowledge on the subject matter? Perhaps I'm too used to engineering style writing which just cuts to the chase. Is it common for book reviews to include those bloats?