Zone tool does recognize column shapes. So assuming you already have a zone (inner-edged) for the room, you can magic wand the zone instead of the blank space to apply fill to the room.
Note that only the columns attached to the boundary wall will be recognized and any independent columns within the room will still be ignored unfortunately. But you can select the fill you placed and activate "Subtract from polygon" from the pet pallet and magic wand click on the zone edges around those independent columns to cut out the fill.
But by all means, magic wand should recognize columns.
Architect | Graphisoft Certified BIM Manager
ArchiCAD 26 JPN USA & INT | Windows 10