I just helped a bud put together a new bike; he's something of a weight weenie, too. Granted, it was nice handling all that bling while I assembled what he couldn't (which was about 2/3 of it), but in his case I can understand it a bit -- not only does he like the best stuff, he's not in good enough shape to spin the mid-range stuff!! LOL!
Another bud, who raced MTB, learned that the best part isn't always the lightest; he looks mainly to performance, with a secondary eye on weight and bling.
Since I'm a Clyde, I don't sweat it; I pick for performance and sturdiness! Sure, I'd love to have X.0, Crossmax, carbon post, and all that; but X.9 does the same job, my 5+-inch travel FS bike weighs less than some dept. store training wheel bikes, and it's still rolling strong after more than 2 years of pounding under my big self! (and the only carbon on my bike is the spacer on top of the stem!)
The problem with weight-weenie posers comes in when riders think their checkbooks make them better riders (or better people) than you on your mid-range stuff that does 90+% of the job for 40% of the money. Now, some will say, 'spank them on the ride, show them who's what' -- I'd rather enjoy my own ride on my own terms. Boink them.