Even though it rarely works out that way, there are sometimes very simple answers. A recent American Buddhist Perspective blog post recently asked a fairly routine question: "Buddhism: religion or philosophy?" It's a religion. Buddhism by its basic principles is a supernatural based belief system, which therefore makes it a religion. It may be true that it is one of the more philosophical religions but that does not make it any less of an organized religion.
Mr. Whitaker throughout his piece seems to make comments to the effect that he knows this already. Throughout he seems to be trying to reconcile himself to the possibility that it could be equally both. I disagree mainly because it ignores a number of common critiques of common theistic assumptions. It doesn't matter if religions are capable of being a specific way if it is possible to be that way without any religious elements. He talks about reducing Buddhism to "techniques" which is the same half-assed argument used in promoting Yoga in public schools. "Yoga" the way many people "practice" it is a matter of technique/method devoid of its original religious overtones. That isn't really Yoga. Essentially you are mixing calisthenics with meditation. It does not require any supernatural beliefs let alone a belief system. Adapting meditative and relaxation techniques from Buddhism does not make you a Buddhist.
If individuals adopted some but not all the various religious based principles along with the methods then you might have more of a debate/question. That does not seem to be what Whitaker is talking about. Buddhism is by its nature a religion. It is just as attached to supernatural thinking and concepts as any other faith.*
I have previously written about Buddhisms supernatural underpinning;
How Atheistic is Buddhism? (12/31/11)
Buddhism and the God Concept (2/24/13)