you are actually quoting the bible to somehow ask why there the world is full of atheists?
FIRSTLY, it isn't.
SECONDLY, why do you imagine it to be a negative thing... after all, religion has been nothing but a source of joy and beauty in the world, right????
THIRDLY, this of us who are lucky enough to live in the developed world now have access to better education and the safety after thousands of years to actually express their opinions in safety.
it woukd be a far more valid question to ask is why many people choose to believe in an indivisible spirit god with no evidence at all.