Irrelevancy in Les Miserables

(Question 14)
The novel Les Miserables is 1432 pages long. Obviously there is some irrelevancy involved. There are, in the novel, three major sections which literary critics of the book refer to as Hugo's "digressions". These are firstly, his play-by-play of the Battle of Waterloo, secondly, his rant on religous orders and lastly, a lengthly meditation on street language. Many more hundreds of pages are filled with what seem to be Hugo's thoughts on a wide variety of topics, some of which are undoubtedly very significant to the plot, and others which are entirely unnecessary.
For example, Hugo expounds for several pages on how beneficial it is for a young man to experience poverty: "poverty in youth, when it succeeds, is so far magnificent that it turns the whole will towards effort, and the whole soul towards aspiration" (Hugo 677), but this is very relevant to the story because at that time in the novel, Marius had left his wealthy grandfather and was himself experiencing poverty. On the other hand, endless comparisons of the city of Paris to mythology are not intrinsically important to the central purpose of the story - "Paris has an Aesop in Mayeux, and a Candidia in Mademoiselle Lenormand. It stands aghast like Delphos at the blinding realities of visions; it tips tables as Dodona did tripods..." (Hugo 586). In addition, these musings are extremely wordy and difficult to follow (although this probably has more to do with my own ignorance than the author's style).
Though I consider the plot of Les Miserables to be extremely well-crafted and gripping, there is a great deal of text that I feel readers could simply do without. The presence of these long and usually unrelated ruminations is more to the detriment of the story than to its benefit.