The program did get some details wrong about the Jehovah's Witnesses. Mostly things like terminology that Witnesses don't use (like "rapture"), a generic Bible instead of their New World Translation, outright saying that Jehovah told them this or that. The Witness organization is careful not to make blatant statements like that. But they did in fact strongly suggest and want everyone to believe that Armageddon would come in 1975 or very shortly thereafter. They praised people who sold houses and property to spend the "short remaining time in this old system" in the full-time service (door-to-door preaching). Then when Armageddon didn't come in 1975, they said that "some individuals" read more into their writings and public discourses than was really meant. But there are recordings of talks by Circuit and District Overseers at several conventions in the early 70's where the speaker clearly said, "Brothers, we have a new date for Armageddon." You can still find these recordings on the internet.
Then there are other details in the episode that aren't exactly right. For example, Jim certainly never sent his wife out for cigarettes. No smoker can be a Witness in good standing. They are usually disfellowshipped when caught. All that said, the gist of the program was correct. Women are to be in subjection to their husbands, and even abused women are strongly "encouraged" to stay with their husbands in the hope he will reform. Disobeying the advice of the elders gets one marked as rebellious and any "privileges" one had in the congregation would be revoked. And there must be two witnesses to things like child abuse or the congregation will take no action other than notify the authorities, and only then if that particular state requires it, and even then they are instructed to report it anonymously. The victim and their family, while not prevented from reporting the abuse themselves, are strongly warned not to talk about the abuse to other Witnesses or the press, for fear of "bringing reproach" on Jehovah's name or worse, the Organization. And of course the congregation is never warned about the abuser by name unless he or she winds up disfellowshipped. Even then, the announcement simply says "So-and-So is no longer one of Jehovah's Witnesses."
It is true that the Society does not condone family-murder and nobody told Anderson that it was ok to do such a vile deed. In fact, the program left out part of the story where the local Elders had found, confiscated, and turned over the police a sawed-off shotgun Anderson had had months before. The police warned him that such weapons were illegal in Canada. He simply bought another one shortly before the murders and sawed off its barrel too. But the whole point of the program was to show that Jehovah's Witness women in particular are so controlled and dominated by the Elders that they are almost forced to heed their well-meaning but uninformed and unprofessional advice in every situation, even to their own detriment and even in cases of physical abuse. To reject that advice has dire consequences to anyone who wants to remain a Jehovah's Witness in good standing.
A point that most people may miss is that there is no way one can leave the Organization with honor. Almost like the Mafia. Once in, you're in, unless kicked out. If you leave for any reason, including a simple disagreement about spiritual matters or Organizational policy, you will be shunned and no faithful Witness, even close relatives (unless actually living in the same household), will speak to you. Divorced Witnesses, regardless of the original grounds, are particularly cautioned to severely limit contact between the children and their disfellowshipped parent. If anyone wants more details on this particular case, check out James Kostelniuk's book "Wolves Among Sheep." Kostelniuk was the ex-husband of Kim and the father of the murdered children. He explains, far more eloquently than I ever could, just how the atmosphere among the Jehovah's Witness community greatly contributed to this tragedy.