My take comes from reading the indictment. The facts stated in the indictment, even if they are true, don't seem to support the charge. And then, as you point out, the actual contents of the tape may be "watered down" from what the indictment claims.
I agree with your assesment. Also the reference to Swat action was a metaphor for calling camera crews to a RAID is well distasteful to say the least. Does not help the credibility of the Supervising agent.
Some more on the tape content may be found at freep.com at the URL I indicate below. The conversation does sound like folks just talkin’ ~ not an organized plan of action ~ and is remarkably like discussions here over the years about the way Eric Rudolph did “twofers” ~ first do a little blow up, or shooting, attract one or more cops, and then do a big blow up, or shooting. He got away with that technique repeatedly. I suppose it does work on some police agencies ~ FBI appears to be among those who act as though they are amazed someone could think up such a thing. http://www.freep.com/article/20100429/NEWS06/100429035/1320/Judge-Prove-Hutaree-planned-attack