Here's a piece from the Telegraph, 'Why being a christian gets you crucified'. Its an interesting article about the furore surrounding Melinda Tankard Reist at the moment. But I don't really think it answers the question "why?". Jesus did.
"The world cannot hate you, but it does hate me because I testify about it- that its deeds are evil" John 7:7 (HSCB; see ESV)