In essence, it is a mental trap. The arguments JWs use are not very good at all, but if they are the only people you are reallly listening to you will begin to agree with them.
http://144000.110mb.com/144000/index.html#intro
This lengthy paper is written primarily for the benefit of those Jehovah's Witnesses who feel trapped by the Society's legalistic arguments and want out. Many are fearful of even glancing at these pages believing that something bad will happen to them, but what they really should be afraid of is not paying heed and the risk of committing an unforgivable sin. When the Pharisees attributed the source of Jesus' power to heal and drive out demons to satan rather than the Holy Spirit they blasphemed the Holy Spirit and committed what some argue is the only unforgivable sin (Matt. 12:22-32).
It is no great secret that the Jehovah's Witnesses attribute the Catholic and Protestant churches' authority to heal, exorcize and minister to the power of satan. But if the Jehovah's Witnesses are wrong, which they are, they are blaspheming the Holy Spirit; this includes all Jehovah's Witnesses who advocate these beliefs through the dissemination of Watchtower Bible and Tract Society literature related to these issues. Rather than dissuading continuous inquiry into the nature and scope of truth, the Bible encourages it for as the apostle Paul cautioned, "be sure of all things."
The Jehovah's Witnesses are hindered in their ability to see their way through the morass of Society literature by four things related to the method employed in analyzing Scripture. First, rather than weighing all of the evidence there is a strong tendency to be satisfied with any answer, argument or supporting fact no matter how weak. But anyone can come up with an answer or opposing argument; lawyers do it all the time. What really matters is whether it is the correct answer, the most valid argument. One must weigh all of the evidence, not just some of it.
Secondly, the Society's theories are laced with hair-splitting and often inconsequential distinctions. Just because the walls in the bedroom are painted green it doesn't automatically follow that the thief buried the treasure in the back yard. Related to this is a third tool used to shore up their doctrines, namely, they too often read things too narrowly which makes it easier for them to deflect criticism. And lastly, one is left with the unmistakable impression that they don't want their own people to really know what the Society is teaching because core doctrine is scattered all over the place resulting in a literary shell game; and great lengths have been taken to muddy the intellectual waters This creates confusion and contradictions to a surprising degree which leaves the reader to rely on the Society's "understanding." Consequently, what might appear to be the work of some lofty, divine will is in all probability the work of some very crafty lawyers, among others.