Prosecuting intent rather than action is a slippery slope at best. The government drops the hammer like this after social uprisings because they want to send a message that they're fully in control. Whether or not that's a good idea, well, that's up to debate. I, personally, think that it will just make things worse, but I'm pretty anti-government. This is a site about a gaming community, so that's as far as I'll go with that.
Basically, it boils down to this: would they have gotten the same sentence if they had tried to incite a riot at any other time? Probably not. And thus, the "justice" system is making up rules and changing punishments as it suits them. I think that's crap, so I'm torn, because I also think scumbags that would burn and destroy their own country deserve a lot of punishment. These are people that are willing to hurt completely innocent fellow citizens because they're pissed at the government. As one or several people have already pointed out, their anger is absolutely misdirected. March on Parliament, march on the palace, march on courts, whatever. But get the attention of the right people.