Could math itself be used to hide free energy?

That argument skips a step. Mathematics can show that a proposed device does not work under its stated assumptions, but those assumptions can be questioned and revised. There is no single mathematical framework that everyone has to use, and a new result can be checked by other researchers.

If a device is claimed to produce more energy than it takes in, the useful test is careful, repeatable measurement with all inputs and outputs accounted for. A claim that the math is being suppressed does not substitute for that evidence.

There is a terminology snag here too. “Free energy” can mean a specific quantity in thermodynamics, or it can mean energy with no meaningful input. Those are different claims. A machine drawing energy from an overlooked source might be surprising, but it would not be producing energy from nowhere.

Math is a way to describe and test a model, not a map that has to be accepted as the territory. If an experiment repeatedly showed something a current model could not explain, that would be a reason to examine the model and the measurements.

Even if a particular idea gets dismissed too quickly, that alone does not show coordinated suppression. There are ordinary reasons a result might not gain traction, including unclear measurements, a device that cannot be independently replicated, or a claim that changes when tested.

The strongest case would be a simple, well-documented experiment that other groups can repeat, with the energy accounting made clear. That gives people something concrete to evaluate instead of having to infer a hidden campaign from disagreement.