Why are Jehovah's Witnesses so "Defensive"?

Nearly Every question I have researched, or asked Jehovah's Witnesses, is peppered with defensive and diversionary answers. All of their main-point answers are cut-and paste when relating to specific scriptural viewpoints. All of the "cut and pastes" are from watchtower or other JW publications. Why are these folks so defensive and outright intolerant of the askers? Their publication; "Reasoning From The Scriptures" was written and arranged in a large portion by "Raymond Franz", a former Governing Body member, who left the group after researching then making his contrary findings public knowledge. If a question is asked by the general population here, and the source used by them is provided by sources who are also critical of the group (with documented proofs of inconsistencies), why do they continue to defend the answers with blanket pastes, then attack the credibility of the asker? Why are they so defensive, not giving an answer with a "mild spirit"?