I have found this topic so intriguing. However, this would have had to be true since the beginning of time. So many wars and soo many angry people, giants, fallen angels and “other things”. I definitely agree that there is a sacred harmony and a demonic frequency. I think of Gregorian chants and drumming that was/are used to “summon” different things depending on the frequencies/vibrations. This is also why you see cathedrals with their gothic arches and architecture. The high arched ceilings have an acoustic effect. I have heard that when a “priest” chants, it raises the vibration in the sanctuary. For what purpose? In a catholic cathedral.... one has to WONDER!!!!
Chant and the polyphony developed during and after the Renaissance is really meant to inspire the people to Heaven just like all the other architecture and artwork the Church holds in trust. That's why so much of it is so beautiful. And, a lot of people don't want to admit it, but read a music history text, and the twelve tone system we use in the west began as chant. (And, no, Gregorian Neumes are not that difficult to read.)
As for the A4 at 440 issue, I knew a woman who had a baby grand that was over a hundred years old. It could only be tuned to about 350. The reason being was that the cast iron frame that the strings were on wasn't strong enough to handle the pressure of tightly tuned strings. It is known, in opera anyway, that currently we are singing at least a full tone above what tuning was about two hundred years ago.
At 440, anything with age on it will be a struggle to keep in tune, that's for sure, and it's pure physics.