And complaining about how the subpoena's asking for tons of documents. Again, every subpoena does this; you have to negotiate with the attorneys on the other side to figure out what they actually want. If SimulaVR was suing Meta, then yeah, Meta will play hardball. But they're a third-party here - chances are, attorneys for Meta are looking for very specific things (namely, economics to support Meta's arguments about the VR market) and SimulaVR will be able to negotiate a way to provide that info without turning their company inside and out.
And if you are asking WHY SimulaVR should be required to provide ANY info at all... well, that's the American legal system. Courts and parties have broad power to obtain evidence from third parties.
Basically, SimulaVR needs to grow up and hire lawyers to handle this.