A lot of details and interviews to soak in. The documentary does start off explaining some of it is re-enacted but not really done so it is an issue. If anything there might be too many interviews as many of them are the same person explaining another step or event in the life of the subject.
I did feel the main take away was how did an individual growing up in Britain get so hateful? It is almost the question of which came first the chicken or the egg? He already had insecurity issues growing up and the pressures of the security and intelligence agencies that started getting involved in his life were probably a factor in only making things worst. Not just one but three of the people interviewed also mentioned that to include General Petraeus who ended up taking over security for Iraq and later the CIA. The General even stated when he took over in Iraq he realized that the camps for security risks were in fact breeding and recruitment centers for Al-Qaeda and other forces.
The post-9/11 world created a lot of paranoia against not just the Muslim world but anyone who looked different and much of the security although it might have been well intentioned it probably created problems as well for many. With the rise of Social media the bad side of it only had a chance for more exposure and people like the subject of the film knew full well how to take advantage of that.
I feel a bit saddened in that one of the interviews, it was pointed out that at the peak of the subjects cruelty, the media knew they were feeding his desire for exposure about the killings and they only covered it more. They should also put some time into explaining how the folks perpetuating such barbarities also have mental issues as well as some stations actually have done that.
I agree with the one critic in that the documentary is not a must see but if you take the time to look at the deeper issue as to why he became a terrorist and how governments, security, and intelligence agencies have to implement policies to make sure they are being respectful of people while at the same time providing security.
It is worth watching for those who want to see one example of how a person did get transformed into a terrorist. The documentary title shows that as the focus as well. It probably could have been presented in a cleared fashion but then it would not have had all the "flash" or eye candy to draw people into watching it.