There is likely nothing that I can say that will convince you otherwise. The security concerns that you outlined in our phone call are so infinitesimally small, and the odds of it actually happening are really remote. A large portion of the security concerns revolve around meetings that are not utilizing any security measures, and I deploy quite a few in every meeting that I do. (I spend quite a bit of time in zoom each week, and have never had any of the problems listed in those scare websites happen.) Also consider that virtual meetings may be a lot of what happens this christmas season.
This conference is only being offered on Zoom, and unless you change your mind, unfortunately you will be missing out on a GREAT conference.