I'm amazed at how certain people seem on either side of this debate. This seems to me like an incredibly difficult problem, and I can't see a solution that doesn't involve significant trade offs.
On one hand, silencing people for "inciting unrest" does sound like something a dystopian judge would say before passing sentence. On the other, there is a philosophical argument—and economic incentive—for Twitter to protect its users from harassment and targeted manipulation, especially when it is state-sponsored.
Where the line gets drawn for these definitions seems to be the hardest part.