"how we can be wrong, how can MILLIONS OF PEOPLE be deluded while you are correct in assuming all the MILLIONS are hallucinating, lying, mistaken."
Millions of people were deluded by Nazism and Marxism.
Millions of people were deluded by the Witch Mania.
Millions of people were deluded by Astrology.
Millions of people were deluded by the "Evil Spirit" explanation of disease.
The number of people who believe something, makes not the slightest difference. You simply do not understand this simple fact. No matter how many people believe something, no matter how many people claim to have witnessed something, etc, makes no difference whatsoever. It makes no difference how "expert" the believers are.
https://en.wikipedia.org/wiki/Argumentum_ad_populum
In argumentation theory, an argumentum ad populum (Latin for "appeal to the people") is a fallacious argument which is based on claiming a truth or affirming something is good because the majority thinks so.