Why cant people (paparazzi mostly) just leave celebs alone?

i can understand that they're famous, and people want to see them, but i think it's just gone way too far for the past few decades... it's not the photos from award ceremonies that i have anything against, it's all the photos of them out in public doing stupid stuff, i just cant see why the paparazzi take photos of other people doing stupid stuff, it's not like celebrities are made to have a flash going off constantly in their face. i just dont get how they can follow people all day every day basically attacking them with cameras, but not getting shot at. if i was surrounded by cameras all day the first thing i would do is get a gun permit and tell them to go away or their camera is going to be in need of great repair pretty soon...