Chainmail. Serves as a faraday cage. Also defends against physical attacks.

tl;dw: A wet towel will absorb microwave radiation before it gets to you. A piece of metal will reflect microwave radiation, blocking it entirely, or allowing you to redirect the energy in a different direction.

If you have a protest sign, line the back of it with aluminum foil to use it as a shield from microwave radiation.

Paraphrased: “It would be unethical for me to even build the kind of system that exists and is used against civilians.”

Speaks volumes.