I don’t think it is uncommon for beginners to separate Zen from Buddhism and by doing so create two, so to speak, separate, distinct piles. There is one for their personal experiences and opinions which revolve around zazen. Let's call this Zen. And there is another pile for the Buddha’s discourses. But this is a mistake. The T’ang Dynasty Zen master Tsung-mi might have thought it also a mistake.
“The scriptures are the Buddha’s words and Ch’an (J., Zen) is the Buddha’s intent. The minds and mouths of the Buddha certainly cannot be contradictory.” (trans. Peter N. Gregory.)
Separating Zen from Buddhism is easy for a beginner to do who just bought Zen Mind, Beginner's Mind or the late Joko Beck’s book, Everyday Zen. These books are made for beginners who want to keep Zen and Buddhism separate; who plan just to concentrate on the practice of zazen. These books are not intended for the serious student of Zen Buddhism.
I am guessing, but more than often the beginner’s interest in Zen, alone, stems from a psychological reason. They want to get their life together. Sitting in zazen sounds like it might help. One can surmise that they are not interested in reading the Samyutta-Nikaya of the Pali canon or the Lankavatara Sutra. This material is, perhaps, too heady for them. Learning to sit Zen style seems like a much better approach. However, what emerges from this approach is a distorted false Zen.
Finding real Zen Buddhism, in which Zen and Buddhism haven’t been separated, is in the academic world and in Asia. This is not to say that westernized Zen is not completely without Zen Buddhism, but it is overshadowed by zazen which makes the separation of Zen from Buddhism much more likely.