Because they misunderstand the notebook's purpose while pestering happy RMB owners in discussion forums, that's why.
The people who pine away endlessly for an RMB with more ports and more processing horsepower are actually asking for a new and improved MacBook Air, not an updated RMB. The Air has all the legacy ports, has powerful processing as one of its core tenets, and just needs a retina display and a thinner/newer design and that's that. Instead of going over to the Air forum and crying about it's shortfalls and the need to make it thinner and lighter, they come here and wish that Apple abandon its strategy by making the RMB thicker and heavier. It's ridiculous already.
"Porsche sucks because it won't listen to us and add three more doors and 6-passenger seating to the 911! I'm not buying a 911 until they get their act together!" Sounds ridiculous, right? Same thing going on here. Endlessly. For over a year.
BJ
I've been following you, and this, argument for the last few months. And I think you summed up what's been wrong with much of the public reaction.
When rMB was first introduced, and to public outcry, I asked MacRumors and Reddit, "why so upset?" and they all essentially answered that it lacked MacBook Air features (i.e.. ports, battery life, processor speed). I asked, "well then shouldn't you get a MacBook Air then? Or a Pro? Since it seems you want Pro features?" but the logic was too much.
I think the problem is people are self-centered—they don't understand the concept of 'consumer profiles' and that they, as individuals, are not the sole target customer in every product release. I tried to explain that this new product category is starting out as aimed for the early adopter CEO/Executive type who wants OS X and a keyboard, nothing more, that they can hand carry from meeting to meeting—and that this wasn't for the average student/gamer/media-mogul/everyman. I also tried to explain that for those consumer profiles there is an Air or Pro with their names on it. But they wouldn't have it. Apple is apparently losing the plot.
To be fair, I think much of the cognitive dissonance is occurring because Apple hasn't updated the Airs to include retina screens. If and when Air's get retina screens, people will finally "see", understand, and finally come to peace with the Retina MacBook, because they can then buy an Air and leave the rMB to the executive types.
(Not trying to act like I'm the smartest person in the world, and everyone else 'just doesn't get it.' I just think its an issue of training. Marketers are trained to see that companies develop innovations as to target different market segments, and positions on the bell-curve according to a timeline of 'economies of scale'. Consumers are trained to think in terms of 'me-me' because that's what makes 'a good consumer' a good consumer (self-centered blindness). If something doesn't hit all their check-boxes, they throw a fit.)
I would prefer people see the rMB as a new product line, one that will mature but stay true to essentialism (OS X with a Keyboard). Once you add 3 port-types and begin needing to add fan/cooling, you start compromising on it's innovation-type and the people Apple is targeting (which again, isn't the every-man).