does not give Jehovah's Witnesses the right to add to the gospel and make Extra-biblical dates and loyalty to men requirements for baptism.
By who’s authority?
JW proclaim they are the authority, the only true religion on earth and God’s agency to the nations. Based on JW being God’s organization you are equivocating.
For example back in the 1 century the apostles had authority from God. There were those that were going around believing that the resurrection already occurred and other beliefs and such of a different faith were not true Christians although believing in Jesus (as brought out in the epistles ) as many do today.
Today, JW claim to have authority from God which gives them jurisdiction on qualifications for baptism. If you reject that, it’s up to you.
However, JW are not adding to the gospels in their interpretation of 1914 either. As JW interpret the gospel JC alluded to the Gentile Times in the future which adds up to 1914 as JW see it.
JW interpretations and claims haven’t been debunked. 1914 adds up and there is evidence JW publish to support it.