I always thought that the Strunk and White was about style - it's up to the reader to decide whether it's good advice or not - but to call it clueless is just wrong. My English improved a lot after reading that book.
Having said that, Strunk and White's book is an abomination of self-contradiction. I can tell by your writing, albeit only a small snippet, that you don't follow their teachings religiously (as some do; IE the Grammar Nazi's - a little knowledge is a dangerous thing). You use your own style for parenthesise (dashes rather than commas), likely one you picked up and liked, and one the Elements of Style suggests is wrong (at least from as much as I've managed to read of the text).