Those people may not have much of a life themselves. The only way for them to feel good about anything is to take notice and immerse themselves in someone else's life.
Some people mistake the on-screen persona and the real person, they forget the actor is...acting. Other people see the masses of people scrambling to get close just to touch them or get their autograph then get caught up in the hype. Actors are like all of us, they have all the same problems and all the ups and downs of life. They pay a big price for their status, however: no privacy, ever.
People are shallow, people want to be entertained, people don't want to have to think too deeply about anything - they want, perhaps need, to be told what to do and what to think, though they will vehemently pretend otherwise, after the manner of deliberately disruptive children. I sometimes wonder whether I, and Dom Pedro II, are the last right-thinkers of our time. [Sigh!]
Randy D 