Why are American celebrities so fake and stupid?

They act like they are really nice and go around the world as if they are heroes and RICH generous Americans...They think less of the world and then go around helping the poor as if they actually care. Is it for the publicity or is it because they actually care. From what i've seen, most Americans are quite fake but why do celebrities reinforce this belief. Since they tend to be popular and known among the public, wouldn't they try and change this perception? But a lot of them do such stupid things, especially jessica simpson, lindsey lohan, britney spears and paris hilton. Do they even know much about the world to help? Lindsey Lohan was recently in India and said "wow, India is industrialized? I thought India was mostly desert...I'm impressed!"...This is a quote and she actually said this. She was there to film a doentary on poor india (what other topic would western media choose when depicting India?") Britney Spears recently found out that Japan is not part of Africa...I really wonder, why such ignorance?