Because -- so I understand, and I am not an expert -- they think it is wrong. Not by any means an undifferentiated heap of nonsense from beginning to end, but wrong enough, in the bits that the naive go geewhizgollygoshwowgeehay over and think they learned something from.

I recall the late Torkel Franzén, undoubtedly an expert, having some strong criticisms of it on sci.logic back in the day, but I don't remember details.