Cults are high control groups that rule by fear and coercion. The God who is love would never use such methods to compel people to worship him. Wicked devils and demons resort to such methods, but the True God would attract people through his love.
Cult behaviour is identified with the BITE model. BITE stands for Behavior control, Information control, Thought control and Emotional control. See https://freedomofmind.com/cult-mind-control/bite-model/. Cults target these areas in your life. These are some of the ways the Watchtower qualifies as a cult:
Disfellowshipping and Shunning
Cautions and warns against reading things online
“Research” can only be done with approved research tools
Requiring members to internalize the doctrines as truth
The teachings are constantly referred to as “The Truth”, no matter if it doesn’t make sense or changes the next day it is always “The Truth”. Repeating this in every conversaion is a brain washing tactic to make members accept it as truth despite evidence to the contrary
Black and white/Us v.s. them thinking
If you are in, you are “in The Truth”. If you are out, you are “in the world”. We will be saved, worldly people will not. We are happy, worldly people are unhappy. We are united, worldly people are not united. We have a meaningful life, worldly people live a meaningless life. We have a hope, worldly people do not have a hope.
None of these are strictly true. “Worldly people” are just as happy and united and have just as meaningful lives and hope for the future as anyone else. Being divided by an arbitrary cult membership does not make a big difference.