If you look at the photos, you can click the right arrow (or top buttons if not on a phone) to see what the neighborhood would look like with eased height restrictions: http://www.washingtonpost.com/wp-srv/special/lifestyle/magaz.... Rather than photoshopping in nice buildings, they've put in windowless concrete slabs of uniform height. Sometimes the best way to get people to agree with your side isn't to argue for your side, but to "push-poll" people: do you like the way DC looks now or do you want massive concrete blocks with no windows dominating everything? In photo mockups, it comes off as subtle, but it can shape the opinions of many.

I'm not saying that's what the WaPo is trying to do. I think they just didn't put in the time to do a good job creating a hypothetical new DC with realistic buildings of varying heights. However, if you support increased heights for buildings, their mock-ups make something you consider positive look bad. I mean, I'd hate to live in a city with imposing concrete blocks with no windows. It would look like some dystopian future world. But the photos of what I think is Chicago that were linked to don't look oppressive and don't have uniformity of height - there's plenty of sky that you can see through the buildings since they aren't connected beige blobs. Now, one can still dislike tall buildings (they can change the nature of the area), but they wouldn't have the same oppressive feeling.

So, the mockups from WaPo look oppressive (on purpose or on accident) while proponents of eased height restrictions would insist that it would look a lot more like the Chicago photos than some concrete dystopia.