A combination of world religion and western humanities courses at college made me make this connection.
The Catholics had a monopoly on Christians until Luther started the protestant reformation. All those who broke off from Catholics went from the pope being infalliable and the source of salvation and full of non biblical traditions and practices to attempts to stick to bible doctrine only and persona interpretation of the bible and no man on Earth as infalliable but that any person can have a relationship with Christ and gain understanding of the bible and God's will.
All those who shifted to the protestant side, since anybody can read the bible then opened up for disagreements with those who were unified. Suddenly you have lutherans, calvinists, protestants, angelicans, etc. To this day it's continued to expand. Most of the churches were independant as well. Like in the bible, each group or congregation picks who does what, etc. Unlike Catholics where everybody reports to the Vatican.
Now the bible students were absolutely no different. They didn't agree with everything so they got together and grouped and agreed with Russell, but with Russell he still taught each person if what they felt was right and scriptures said conflicted with his interpretation to go with what they feel. Also the congregations were independent.
Now comes Rutherford. He is the new pope, he is infalliable, he is the direct channel. He also has all congregations report to him. He has the say on what is and is not right. Takes away the freedoms of congregations to disfellowship how they choose to his calls the shots and instructs the elders how to do it and what to do. All exactly like the Catholics. Everything he condemned the Catholics for doing in later articles he adopts.
Jehovah's Witnesses religion is born and adopts the same model as Catholics have been using. They seem to have completely left the reformation and protestant line.