Sounds like a classic case of both the moderates and the radicals being essential for any real change. The moderates are the hammer and the extremists are the anvil.

Society is like a bar of iron. It’s stuck in its shape and resists change. Non-violent moderate protest alone is like a hammer without an anvil. You strike the iron, but the iron ignores the blow. With moderate protest alone, the established powers simply ignore the protests. They bend and duck out of the way and nothing changes. But violent groups serve as the anvil. They hold the powers that be in place and prevent them from ducking away from the hammer blow of the moderates.

Both hammer and anvil are needed. Without the violent extremists, the moderates are simply painted as extremists and ignored. With them, the moderates can actually gain traction. Moderate protest movements don’t succeed unless there is also a violent wing. Moderates are only moderate if there is something to moderate against. Without the violent extremists, the moderates will be the ones labeled criminals and arrested, regardless of how extreme their tactics actually are.