How do you propose the site be restricted to those who only follow bible principles? Ban the Athiests? Who would decide who got to post? Who would decide what was Christian enough? This site is actually owned by Simon, it is open to all who follow the posting guidelines, which I feel are reasonable. Many times what new posters see as mean spirited arguing is just healthy debate. As a Jehovah's Witness we were not allowed to do that, it was the Watchtower way or no way. Yes, there were no (known) fighting, because those who disagreed were disfellowshipped. That was peace at the cost of personal choice and freedom. We don't do that here.
As many have pointed out, there are a lot of other sites that are focused on those who still want to follow the bible. You can also stay here and just avoid the Athiest/believer threads, you may have noticed that those threads are in a particular section, just avoid those.
But I challenge you to look past the labels and read and consider what everyone has to say, who knows, you might learn something, I know I have learned a lot from reading here. And you are certainly free to post your beliefs. Yes some will challenge you, but if your faith is strong, it should stand up to that. Don't become insulted if some disagree, even emphatically, with your opinion. It's not personal, they just believe in their viewpoint, as you do yours.
So, welcome to JWN, please, start a thread and tell us your story, or as much of it as you feel comfortable telling. I love to hear how people got into and out of the religion.