Yeah, this is trouble, because the common understanding of "hologram" is very different from the actual definition.

As far as I understand it (and another person has explained it better below), the indication is that the way we perceive the universe indicates that the "data" producing those perceptions is not stored in the same structures we see or detect - instead, those structures (space, mass) are sort of "implied" by a more fundamental way of "storing" that data, which we interpret secondhand because we can't perceive the original. Not sure if this is clear or accurate, but that's what I've taken away from previous articles on a holographic universe.