I think the thing is that different people are commenting. People who say "needs more x, y, z" here are not the same who say "it's too heavy" or whatnot on some other thread.

Also, people who think this laptop is just fine (I don't need more than 16G of memory, and HD is fine for me too) have little to comment about, or the only comment they really have "hey, looks cool!"; which are kind of the unsubstantive comments HN discourages. So by and large, those people won't comment. But people who do have something they want to see better do have substantive things (or rants...) to post about the keyboard, screen, memory, or whatnot, so they will post them.

In short, you're 1) seeing a very biased view of what people think, and 2) HN is not a "hive mind" where everyone agrees.