There's this group that pokes it's head around here from time to time that call themselves that, or "anarcho-antirealists." They claim that objective reality, including physical laws like gravity, are "oppressive" and only exist because people believe in them.

So gravity is something you consider unjust?

Yes. Gravity does not ask one’s consent before pulling.

They're a bizarre, annoying cult but seem mostly harmless, they're just roleplayers who forgot their dice.