This subject is always framed incorrectly. It's always frame around ionization energy level and penetrating depth. They completely ignore the science of resonance, the science that makes sending and receiving signals possible. An opera singer can shatter a wine glass with non-ionizing sound. In the Earth's magnetic field the proton resonates at audio frequencies of around 2 kHz. The science of chemistry by electric means has really been advancing lately also.

By long term exposure utilizing frequency interaction, like beat frequencies and modulation, with the knowledge of the combined resonance of complex groups of molecules instead of just targeting a single.... With this knowledge there really are no energy or frequency levels that are safe from a technology advanced enough desire to do nefarious harm by frequency.

It really boils down to trust. With the reaction to force this on people it sure shows intents that are not good. Whether those intents are for electronic tracking, surveillance, or other leash systems, or if they go further into harm by frequency who knows.

proton frequency source https://en.wikipedia.org/wiki/Earth's_field_NMR