The Pittsburgh Two weren’t arrested for committing, or facilitating any real "crime." They were arrested because agents of the state fear and loathe any gathering or event they do not control, and any use — or even possession — of tools or technology which might conceivably reduce or frustrate their ability to do ... well, whatever the hell they feel like doing.
That fear and loathing is entirely justified. Every major new technological development threatens the status quo, and the increasing pace of such development over the last few decades makes for a grumpy, embattled state.
The trend has only gained momentum with the introduction of things like networks which don’t depend on single central servers, or which operate easily across the imaginary lines politicians draw on the ground to mark their turf ("borders"), or which are impossible to snuff out by taking down a single node or even a set of nodes.
These newer technologies terrify agents of the state for two reasons.
GMTA: While I was writing that article, Mike Gogulski was recording a C4SS audio commentary that takes a similar tack.