I had read that arguement before, and it makes sense in a way.  I haven't experienced specific entity contact as some have while spicing, but have had (or perceived) to have contact with large visual morph i felt had its own intent while on other consumables.  my experience with the spice has been vibrational as well as visual. 

I would see entities as more of our projection (but not in the sense of it not actually existing) but more of our perception of its existence as we would like to or have been conditioned to see or experience.