Not only is it a cult it is demonised.
Just take a look at the demands it makes on it's followers:
Sacrifice your sick children to the Watch Tower God by refusing an organ transplant - blood is an organ by all definitions.
Deny Christ as your personal saviour and acknowledge that the Governing Body is your saviour.
Blaspheme the memorial of Christ's death by refusing to partake of the wine and bread which signifies His perfect body and blood sacrifice which he gave in mankind's behalf.