How do you call this religious belief?

Antitheism is one word that can be used for that. According to the article, other words include dystheism, and misotheism.

Transtheism is sometimes used to describe a system that believes in gods, but in which gods are transcended.

http://en.wikipedia.org/wiki/Anti-theism

An insincere belief. Belief is an integral part of seeking God so you can't have a belief without seeking. We act on beliefs; that's why we have beliefs.

An opinion, on the other hand, does not involve taking any action. So this person who says they believe probably only is expressing an opinion.

If you believe in God then you do follow him, albeit in your own way. Its perfectly possible, and probably very sensible, to believe in God but take the opinion that all the organised religions are wrong and you don't want their guidance. So you live your life by what "your" God would want you to do - hence following God.

Theist.

Not all belief needs to fall under a preset structure or society, you know?

A non-practicing theist.

Carlin's one commandment: Thou shalt keep thy religion to THYSELF!!

Its called 'hypocrisy', and its America's oldest and most-loved tradition.

It allows people to be arrogant and self-righteous (more American traditions), while actually doing nothing (America's favourite pastime)

Death. I speak the truth.