Otherwise, though, I agree that for progress to be made a non-violent movement must be present. Being a violent movement doesn't really work unless you've got outside support against your state.
That said, and to speak to the implications you mention, it is my firm belief that while a violent movement is doomed to fail it still must exist for the non-violent movement to make progress.
If the choice is between listening to the vocal but peaceful minorities and ignoring them, the choice historically is to ignore them. Once the minority's voice is seen as a less-costly alternative to dealing with violence, the state tends to listen.
MLK had Malcolm X. The LGBTQ folks had the Stonewall Riots.
It's a bloody and inefficient way of making policy, but it seems to be the course of things.