Obviously the show is grade A copaganda. Fincher has always really loved the idea of a bunch of unhinged psychos lurking behind every corner to get you. Really plays into the thesis of Programmed to Kill, which is that the feds/CIA created the idea of the serial killer to cause fear and chaos in the public so that we would welcome the police state we currently live in.
Its not though, Terry is gullible and so is McGowen cause he took fucking Henry Lee Lucas at face value too and believe the hand of death bullshit, he even refers to Henrys "considerable skills" when the only skill Henry was ever really proven to have was lying and stabbing people like any other person who might try to stab someone, for all of his 3 or so confirmed murders he can only describe the process as something like "punching them with the knife". There is absolutely no evidence or substance to Lee Lucas's stories and he never displayed any of the skills he claimed to have been taught by "The Hand of Death".
He even openly acknowledges that the cops used Lucas as a tool to clear cases yet still pretends that the lack of consistency in method and process is a testament to how well trained and versatile Lucas is rather than the fact that there is only evidence to connect him to a handful of murders, all basically done in the same style of "I had an argument with a person and then I stabbed them suddenly".
He literally quotes Lucas and Ottis Toole doing a fucking improv "yes and" bit but for inventing a serial killer story and acts like its evidence. Like it literally goes "Hey remember when I ate that person, why did I do that Henry, remember when I did that?" and Henry goes "Oh yeah, well it was the devils doing that made you do it", like its that level of stuff.