Why do christians belittle the mormons?

Alot of the christians on here think that since mormonism is a relatively new religion it must be bs..i have also seen some who say it is not "sacred" as christianity is.. that the book of mormon was written by quacks.. why the hipocrasy?? christianity was written by illiterate mysogenistic men 2000 years ago.. it isnt even as old as hinduism believed to be 3700 years old.. what gives christians? why the superiority complex?