the problem the author of this article has is they don’t believe Jesus sent the Holy Spirit to lead the Church into all truth. so when the Apostles spread the Faith over the Roman Empire, and the One Holy Catholic and Apostolic Church formed, it had authority to teach and baptize. it had authority to teach true doctrine because it received these doctrines directly from the Apostles under inspiration of the Holy Spirit. doctrines received universally from the Apostles were accepted, if it wasn’t from the Apostles it was rejected. this is the standard the Church used in determining which books that claimed to be Scripture were part of the canon and which were not. but vain men long ago rejected this Church and it’s authority and started deciding on their own and using their own minds which doctrines were true or not. so doctrines received from the Apostles and believed for 1,500 years on baptism, the Eucharist, the Church, the Bible, etc. were thrown out the window overnight. the result? mass confusion and heresy. everyone is their own pope and every doctrine is up for discussion. some groups are close to historical Christianity such as the Lutherans, others like the JW, LDS, SDA, COC, Baptists, Oneness, etc are way off base. once you reject Jesus and His Body on earth, The Church, you get chaos and rebellion. the devil must be proud!!