Isn't being a half hearted Christian worse than being an atheist in the bible?

Both are lost, but the Atheist [hopefully] knows it, so there would be more hope of him finding salvation. Salvation is like a marriage contract offered to mankind by the Savior YAHOSHUA. Take His name, follow His rules (Torah) you become His ‘bride’ and He saves you. If you and He have become one, His mind will be in you , and you will choose to do those things that please Him, and you won’t break His commandments.