The whole purpose of Hollywood is to make money...and if they obscure the truth, the audience isn't going to see it. Though I must admit that it is really scary to believe that people get their "truth" from Hollywood.
If the whole point of Hollyweird was to make money, they would make more movies like The Chronicles of Narnia and fewer like Brokeback Mountain.
But they don't do they?
Hollyweird ain't about money.