I think the reason is simpler, their lives are boring and they were raised with stories of great heros slaughtering monsters that they often compare themselves to. What would you rather have, a life were you go in punch a clock, do a job you hate, go home, sleep. Or would you want one where you are an underground freedom fighter whose life is always on the line and every action you take is critical. Sure it makes your life more stressful but it makes mundane things seem exciting and worth living for. Everything becomes exciting going for a walk in the park becomes daring the bigots to attack you in the open, going out to eat becomes a life and death struggle on whether or not your waiter poisoned your food, buying a coke becomes a way to show those bigots you can buy whatever you wish, going to a riot isn't you destroying homes and lives you're fighting evil, hell even watching T.V. is considered an act of rebellion to these people since they are supporting ((("Radical"))) opinions by watching T.V.
It be exhausting but most of these people have horrible lives in jobs they hate, relationships they can hardly keep together and self destructive habits. They have no accomplishments under their belts or things to be truly proud of so they have to fabricate meaning out of their everyday actions.