Radical? Sure. Terrorist? Nah. Liberals (and especially right wing libs) are violent towards marginalized groups and literally the planet itself, among others. Marxists, anarchists, etc. are violent towards capitalism and those who seek to uphold it. Revolution takes shape in many ways and some of those are violent, particularly towards the end. Don't act like the system we're living in isn't abhorrent and violent. Politics in all of its forms boil down to violence. What are you seeking to build, what needs to be destroyed, who stands in your way, and what means are you able to use? That's politics in a nutshell. Answer those questions for the majority of governments the world over and then answer them for your left wing Boogeyman of choice. Which sounds like it's worth fighting for?