Seems to me that finding people who are planning on committing mahem is one of the reasons we have an FBI, isn't it?
As long as they're busting people who were attempting to commit a terror act, and they're not goading people into deciding to commit terror acts, I say the FBI is doing its job and I am GLAD they are.
So it all comes down to what the ORIGINAL intent of the perp was.
Was he ALREADY committed to doing violence before the FBI started playing along, or was he lured into some kind of conspiracy by the FBI agents?
THAT is the question.
That is always the question in cases like these.