Kathy O'brien is a 'conspiracy theorist' who builds on various MKUltra stories. Her basic narrative appears to be true, but probably has some details in error.
Maury Terry was a 'conspiracy theorist' who believes there was a network involved in the Son of Sam killings. His basic narrative is probably not exactly true, but is reflecting a very common worldview which most people are not aware that they hold.
There is no direct connection between these two people, but both are examples of individuals trying to update the popular worldview by re examining facts.
The normal progression in forming a worldview, for most people, is to observe a set of facts, or be given a set of facts, and then to be presented with a context in which those facts exist, a partial worldview. Most people have a background more or less in common, watched similar tv shows, heard similar news etc, so a partial worldview usually will lead most people to the same place.
When somebody tries to present an alternate worldview, usually in the smaller sense i.e., with regard to some specific issue, it's often based on an experience that is not common or an education that is different from the common.
An established worldview already has a vast terrain, a landscape, and new facts only need to find their place. In other words to perpetuate a common worldview using new facts is usually easy. If you are taught that ghosts are responsible for many things, and your sock disappears in the dryer, ghosts are probably responsible.
Kathy O'brien was abused as a child. There isn't much doubt about that. Abused children don't really have any worldview in which to explain their experiences though. There is no clear world that can be built around having been abused at an early age. So abused children necessarily are caught in a riddle of trying to incorporate something that can't be easily explained, into a worldview of hard facts which overlaps common worldviews. In other words, as an abused child ages they have to fit their actual experiences into a world that contradicts those real experiences. Like a person who, when they were a child, saw only blue trees, then as an adult sees only green trees. The child has to find an explanation for the two different 'logics'. The common tool used to bridge that gap is to portray a certain specific group of people as being 'different', as being 'evil'. Thus the adult, any formerly abused child, can both reconcile the gap between the two worldviews, and, constructively reduce the harm caused by the type of experience they had, by further segmenting the world into 'evil' and 'good' people.
In Kathy O'brien's case she has access to more data, more facts, than most abused children, but she does not have a clear landscape around which to place her experiences. So she takes what she does have, her experiences and her familiarity with the world, and melds the two together. Because she necessarily fills in some blanks from her imagination, some facts are not exact, some observers will discount everything she says based on that, despite there being unusual corroborating evidence of her most extreme 'conspiracy' claims.
Maury Terry was a journalist who tried to construct a worldview in which various serial killers and similar types were connected via an abstraction, in this case a specific group which was focused on 'evil'.
A worldview does not go far in just one person, so in the Netflix series he tries to recruit David Berkowitz into his worldview, believing that facts which Berkowitz has access to will flesh it out, make its landscape visible to others.
He tries to do the same thing police often do when solving crimes i.e., weave facts into a narrative and get a 'critical mass' of people to accept the narrative, at which point it becomes fact and appends on to the pre existing worldview.
But he has a number of challenges.
His biggest problem is simply that David Berkowitz may have a strong motive to support his worldview by fabricating facts. Maybe he will get out of jail or get some other benefit.
His second problem is that his 'new' worldview is not properly articulated, so cannot be properly shown to be true or untrue. He was trying to use a common identifiable group, a series of 'Satan worshippers', as the underlying thread which connected several crimes including the Son of Sam killings. So his worldview started with the notion of 'bad' and 'good' groups, a very common element in popular worldviews, then tried to build on that. If he had gotten enough strong facts to support his factual claims he would have had a headstart in supporting his weaker starting notion.
In a broader sense though, it is the general public which loses by not being easily free to examine the worldview in which the Son of Sam killings occurred. The killer was labeled 'an individual killer' i.e., he acted without influence from broader society etc and is alone responsible, and thus accountability is his alone. This makes it attractive to join groups which assign accountability, like law enforcement, because it allows a person to join a group within which they can build a worldview where any natural accountability they would face is temporarily, unnaturally, transferred to a vulnerable party i.e., usually an individual not as powerful as the group.