That's not how I read the comment. Between the "easy to pick up from here" (downhill parking) and "hard to pick up from here" (uphill parking) there is the most likely most common "indifferent" (parking flat). The main theme of this article is to try to always park downhill. So, an interruption that is anything than parking downhill is to be avoided. The claim is that you spend the vast majority of your time at work not facing downhill. Intuitively, that makes sense.
You really think so? You think you spend the vast majority of your time at work doing things that are so complex they're hard to pick back up 12 hours later?