Remember also that producers of these shows often do have contact with members of the intelligence and defense communities who serve as official or unofficial advisors, at least so long as the depictions are acceptable to the establishment. Through these advisors, entertainment producers learn about secret programs long before the public. Kathryn Bigelow's Zero Dark Thirty is a particularly prominent recent example of how this works, and why it is a bad thing that results in "entertainment" which is very much a form of propaganda.
I'm not sure what point you're trying to make. Are you saying that the producers were rewarded after the fact, for the pro-torture message? And that encouraged them to make Season 4 even more torture filled? What sort of "insider information" did they get?
Portraying torture as merely "morally ambiguous" is arguably fairly strong pro-torture propaganda by the standards of anything but later editions of 24.
I don't know how many people here really remember the mood back then. I was just starting college at Georgia Tech when Season 2 of "24" came on. It was hugely popular in my dorm. And the overall sentiment was pretty violent. In the run-up to the Iraq war the next year, it was less controversial to say that we should turn the middle east into a "glass parking lot" than to argue against going to war. And this is of course among people who were relatively liberal compared to the region as a whole.
http://24.wikia.com/wiki/Torture
And an amputation page:
http://24.wikia.com/wiki/Amputation
(but a couple of those incidents don't involve torture; I remember being extremely put off by the scene in day 8 (I guess I switched it off before the scene was complete).
Now I wonder how mainstream 24 really is, given how over the top it seems.