I'm not saying that weight's not a consideration, just that it's not the most important factor to consider. Sure, if you had two jackets with good fit, breathability, sufficient durability for your intended use, features that work etc, then it would be logical to buy the lighter one, erm, as long as you like the colour of course 
More generally, I think people need to get some perspective on light weight. By its nature, cutting weight tends to get a bit obsessive sometimes at the expense of function. Often the first thing to suffer is durability; generally lighter kit isn't as tough unless it uses very expensive fabrics and components - 'strong, light, cheap , pick two' - and often the buyer hasn't quite grasped that. Really light kit demands that the user has the skill and knowledge to use it properly.
At an extreme level, you could - conceivably - go climbing using a plastic carrier bag as a makeshift pack. You can see the blurb: 'Minimalist, light, waterproof and packs down to near nothing, the Tesco Alpine Extreme is a cutting edge climbing pack etc'. And technically it's true, but it relies on the user to understand that it's also not very abrasion resistant, has a very limited load capacity and no straps...
Okay, that's a somewhat daft example, but if you're going to buy, say, a sub-200 gramme waterproof shell, you also need to understand that it may die fast if you insist on using a pack, that the very thin face fabric may be prone to wetting out, that a short, fittted cut may offer less protection than a more mainstream jacket, that you will not have a map or hand warmer pockets and so on.
If you're aware of that, then fine. The problem comes when people have unrealistic expectations because what they want are the qualities and features of full weight kit but in a lightweight package. That's happening up to a point because fabrics are getting lighter and something like Gore's Pro Shell has cut weight relative to XCR, but is actually more durable...
Anyway, I do take your point, but I think it's actually quite a lot more complicated than it looks 
