'twas a bit more than organizing protests
What I read was that he was arrested afters comments calling for violence were posted from his IP (calls for Molotov cocktails, if memory serves). As he is running a TOR exit node, it is entirely possible that the calls were made by someone else entirely. In fact, if he can prove that he was not at home at the time, and if the Russian judiciary is less dense than it's murkin counterpart, he should be in the clear. Wich, of course, means that he's screwed.
Don't be an ass, don't use TOR for illegal activity, especially when you know you'll need an exit node (i.e. TOR-to-clearweb)
Note that French law makes the leasee of an IP legally responsible for every bit of traffic bound to that IP, better secure your WiFi APs and not run an exit node there...