I can speak to this with some authority; though I am somewhat biased (I was hired to help promote Der Baader-Meinhof Komplex a bit in the in United States, and I am probably North America's most knowledgeable expert about the Baader-Meinhof Group.)

So, specifically in regards to The Baader-Meinhof Komplex; by most ways you want to determine "accuracy" it's a fairly stunning achievement. An example to the lengths of historical accuracy the producers went to is during the opening scene at the June 2nd, 1967 riot in Berlin. It was filmed at the exact spot of the original riot; the clothing, the hair, the uniforms, everything has an exact match in the historical counterpart; they even linger on a news kiosk for all of a few seconds; yet every single magazine and newspaper shown was an exact reproduction of what would have been seen on that date.

This attention to detail is carried on throughout the movie. It was written (and produced) by Bernd Eichinger, who also wrote "Downfall" (you may know if from the 10 million "Hitler Screaming" subtitling mashups on youtube. It was based on Stefan Aust's masterful 1988 book "der Baader-Meinhof Komplex. Aust's book was factual to a fault; it almost reads more like a diary and rarely ever went off into unsupported territory. It's clear they made the same effort for this movie.

That said, there are some areas where they took artistic license; for instance in the murder of the Banker Ponto, there has never been a published account of what actually happened. So they chose to infer how the murder took place. But the Ponto family sued the producers for apparently misrepresenting the events. Also, you may have noticed a woman terrorist in the end of the movie; she is let out of jail, and then goes on to lead the members of the group that are not in prison. This is based on Brigitte Mohnhaupt; who became the leader of the group in the 80s. She sued the producers because they show her hooking up with a supporter right after her release from prison. She was, apparently, upset that they indicated that she had sex; she claims she didn't. And yep, she sued over it.

But that's basically nitpicking; it's slavish in it's adherence to facts.

That said, many have claimed it's essentially the worst movie ever because it showed the terrorists to be mad men; motivated by nothing. And others felt it glorified terrorism. I believe both of these critiques reveal much more about the person making them than the film itself.

My main critique of it was the decision to create an "immersive quality"... to not introduce characters; to just have people show up without explaining who they were or whether they were important. I probably know these people better than all but a few people; but even I would get confused (and this was definitely the intention of the writer). SOMEDAY I'm going to put together a commentary track to help people understand what the heck is going on on the screen!.

Here's a review I wrote of the movie when it came out: http://www.baader-meinhof.com/der-baader-meinhof-komplex/

Here's an interview I did with the writer/producer; we talk at length about the accuracy of the film: http://www.baader-meinhof.com/interview-bernd-eichinger-writer-and-producer-of-the-baader-meinhof-complex/

In terms of Carlos; I don't have anywhere near the background in Carlos' story; but my general sense was that it was both fairly accurate, but did invent some things. It's also a masterwork. In the small world of movies about left wing terrorism; Carlos stands heads and shoulders about everything else.

In term's of Hitchens thesis; first off... when that article came out I almost lost my lunch... one of my favorite writers clearly used my site as a resource for his research. Holy smokes that was exciting.

That said, his thesis former Axis countries giving rise to these terror groups is interesting; if a bit selective. The theory "works" if you, say, ignore the Weather Underground in the US, or Action Directe in France, or the CCC in Holland, etc.

But he is absolutely correct in talking about the Baader-Meinhof Group (Red Army Faction) being a response to these students' parents generation of Nazis. I've written about this before in Ask Historians; and also write about it extensively in the intro to my book: http://www.baader-meinhof.com/the-gun-speaks/intro-chapter/, but a short TL/DR is that they believed that Germany was still secretly controlled by fascist former Nazis (and to some extent they were correct). They believed that if they attacked the state, the state would respond with massive retaliation; demonstrating to the proletariat the "true" nature of the fascist beast and they would independently rise up and create revolution. In THAT assumption, the Baader-Meinhof folks were very very wrong. The German people mostly applauded and supported their government's efforts to quell the terrorists. The people, were, after all, German.

EDIT: I missed that you mentioned "Terror's Advocate". Wow, what a great documentary. I can't offer much beyond that because it's mostly a talking head documentary; you pretty much have to take what people say on faith. That said, I haven't heard anything to contradict what it said.

Some other films you might enjoy:

Protagonist; a truly odd and truly well made documentary that features, among other things; an extended interview with Hans Joachim Klein, who was also in Terror's Advocate

Starbuck: Holger Meins; about a member of the Baader-Meinhof Group who starved himself to death in prison on a hunger strike

Stockholm 75, a documentary about the Baader-Meinhof takeover of the West German embassy in Stockholm

The Legend of Rita, a narrative fiction film based around the 11 former Red Army Faction terrorists giving housing and hiding in the Former East Germany in the 1980s

The Lost Honor of Katharina Blum