In my view the “flat earth” people are simply seeing things in a hyper dimensional (collapsing the wave) mode. They are seeing a Planet “plane-net” from the point of view that reduces everything out of the hologram view into a sort of continuum of unlimited horizons viewed condensed, as in, down to the “thought” of source vs. the multi-dimensional aspects which allow you and I to navigate and go deeper into the quantum moment for the purpose of ‘experiencing the whole'.
It is similar to the way we view time. We see time as linear when it is actually simultaneous. In reality, time is an illusion. All things happen simultaneously. Well, if space is viewed the same way you could in essence say there is no space… space is an illusion or hologram. Everything it is at the same time infinite and infintesimal and can be reduced to a single point.. zero point or simultaneity.
I also see this issue coming to the fore at this time because of the transition of Earth from 3D into 4D. Because 4 D can be visualized a a horizontal endless plane and is inhabited by many races of ETs it is being perceived now as the veil is thinning between the dimensions. As humans activate dormant DNA their perceptions of what we call reality changes. They begin to see through and into the dimensions and interact with those dimensions more consciously than before.
Also see Ashayana Deane's VOYAGERS books for a greater understanding of the multi-dimensional nature of reality.