Oddly enough, the jury apparently felt so strongly about this that it even went beyond the rejection of the DAs "conspiracy" theory. Look at the simple charges of "possessing a firearm in a federal facility". They were shown in the news, on TV and the Internet at a federal facility while possessing firearms. They never denied that. And they were acquitted.
I am surprised that there was jury nullification though as they did not seem to be well received in Oregon and even the people they were protesting for wanted them to go away.