The quack medical advice that was/is offered through the org/society is simply a reflection of the people who made up the early Bible Student movement (and that influence and legacy is still manifest today).
The Bible Students had several members who were alternative medical practitioners. If you trace the history of alternative medical practitioners and their legal struggle for the right to practice, you will find that the WTS' legal battles for "religious freedom" dove tail with the chiros and osteopaths fight for "medical freedom". The WTS' medical propaganda was solidly anti-AMA.
An example of how an early Bible $tudent$ influenced the WTS writings is Dr. S.N. Wiley. He was a medical doctor who had lost a patient after a reaction to the diphtheria anti-toxin. Needless to say, the WTS became one of the leaders in the anti-vaccine movement.
And, those wacky quack medical notions were usually attached to some kind of device or instrument that a Bible Student/JW wanted to sell - we must not forget the Judge's radioactive belt, the Abrams electronic box that was used at Bethel, Wm Hudgings 'asshole flusher'....etc.
The WTS' promotion of quack medicine and quack science is simply a reflection of those who have used the 'society' as a vehicle to promote ideas that wouldn't get accepted in mainstream circles.