Perhaps. There seems to be a lot of people who seem to have thought what I thought, though. Maybe it would be better if they gave an all-out disclaimer saying that, "no, Soylent cannot be considered as a replacement for your balanced diet"?
From his blog, he really did seem to push the idea of making Soylent his only food -- IIRC he felt like that the traditional idea of eating from a lot of different sources was stressful (I guess the decision of what to eat, etc, was stressful). His blog seems to be down for me right now, though, so I can't confirm that.