it's only about loyalty to an organization--has nothing to do with god!
The JWS heads (GB) claim to be god's spiritually chosen ones, so to object to their expressed doctrines (bible interpretations) is in kind objecting to god Jehovah an act of apostasy.
Likewise the ancient Hebrew high priests could have one of their citizens killed for acts of apostasy if the person was persistent .
A semblance of power and control supports those men who are at the the top of the power structure which can be seen in most organized religions.