Actually, Dr. Thiel's study leaves open the question of whether or not the original Clark zapper could kill microbes. Your claim has been refuted by several videos on youtube and other places that shows the original Hulda Clark zapper actually does kill some microbes under microscopic observation.
Also, these was a member of the Zapper Support Forum many years back that posted photos of zapped microbes in petri dishes that clearly showed that microbes were killed by zapping. Sadly, I believe that those photos were lost in a hard drive crash.
Regardless of any of that, the fact that multi-frequency ParaZapper can and does directly kill a wide range of microbes is definitely provable.