If it was just a case that hardware capacity has reached a point where most of us really don't need to upgrade our computers any more, that would be one thing. But the article also says that many of Apple's decisions are making their laptops less recyclable - even if the actual materials they're being made from are more so. This is a serious issue that people should care about.
People should also care about not being able to replace their batteries. Even if the rest of the hardware remains useful after 2, 3 or even 4 years, a battery is a consumable. It gets used up. In the article, it says the original Macbook Air was rated for 300 charges. That's not a lot, and since you can't replace it, you're going to find yourself buying a new laptop in 2 or 3 years even if the rest of the hardware would have lasted 5 or 6 years. And your old laptop won't be recycled either, because they decided to glue everything together.