More like, everything is so unrealistic and baseless that it becomes fantasy. Apparently there exist multiple plane of existence, one can shift his consciousness in different bodies, we haven't even clearly defined what consciousness means (one of the biggest meta physical debate), the singularity is possible (in fact some did the opposite), giant floating crystals is possible, there exist transcendent extra planar beings...
''Every thing is brain farted out of tin air, so why not just call it fantasy'' is basically the reasoning.
And that comes from someone who just backed, because that doesn't mean it won't be entertaining.