The author is misleading at best, and wrong at worst, regarding Mad Mo as the onyl founder of a religion mentioned in a “contemporary source” - whatever her actual definition of “contemporary” is - either by a specific date range, or merely a secular source, or a source not of the religious founders’ own religion.
Jesus Christ is mentioned in the works of Josephus, a jewish historian, not a Christian. Also in the writings of the Roman senator Tacitus is Christ mentioned being crucified under Pontius Pilate.