you’re thinking upside down.
The supports are not columns- they are cables in tension.
the model hangs upside down in the printer, and Preform adds diagonal members to try and keep the cables stable in x and y dimensions- but the primary concern is keeping the layer position in the Z axis accurate.
Diagonal members, in being built, would have a free end cantilevered such that it would be able to deflect as the the platform lifts.