You're probably being downmodded because half a pound of weight is not a major feature, but you're trying to shoehorn it into a trump card. For me, the trackpoint mouse is a major feature which leaves the Air dead in the water, but it's really a minor feature between the two.
Same as all the extras that the X220 has over the Air, like card slots, swappable batteries, and a perimeter that doesn't cut into your hand. And vice versa. These things are all minor differences. The Thinkpad laptops are also as tough as the Apple laptops, if not tougher - despite looking like a normal laptop, they survive more military tests than 'hardened' brand laptops.
The short version is simply that the Lenovo X-series and the Apple Airs are equivalent laptops at the same price point - the Air is not 'better' for 'less' than the 'inferior' product.
It may sound odd, but last year I had a 13" MBP (4.5 lbs), and its weight really bothered me. I actually swapped it for a mac mini that I carried to and from work each day, hooking it up to a monitor, keyboard and mouse at each place just because it was a bit lighter.
The only I'd want an air over a pro is the weight. As far as the X220 is concerned, weight would be my number #2 complaint after the OS. The lack of an Apple-level quality trackpad might be #3. The hundred bucks does matter, but honestly when you consider how many hours you, or at least I, spend on a computer, the price is almost negligible compared to improvements in user-experience or efficiency.
Same as all the extras that the X220 has over the Air, like card slots, swappable batteries, and a perimeter that doesn't cut into your hand. And vice versa. These things are all minor differences. The Thinkpad laptops are also as tough as the Apple laptops, if not tougher - despite looking like a normal laptop, they survive more military tests than 'hardened' brand laptops.
The short version is simply that the Lenovo X-series and the Apple Airs are equivalent laptops at the same price point - the Air is not 'better' for 'less' than the 'inferior' product.