i do not believe atheists just lack belief

Is atheism just a lack of belief?

1:saying ''i just lack a belief in God'' seems to mean that you are not really making any claim about God,you just don't have a belief in God and you are unconvinced 

ok,to make my point i am going to make more levels of beliefs/non-beliefs and explain why the claim ''i just lack a belief in God'' doesn't work on atheism

Atheism-------------Atheism 2------------Agnosticism-Theism-----------Theism 2

---------------------------_-------------------------_--------------------_----------------------_---------------

there is  no God     it's unlikely          i don't know   God probably   God 

                                 that God exists                           exists                Exists

now,saying ''i just lack a belief in God'' seems to make sense on agnosticism

that is to say:i don't have a belief in God,i am unconvinced

this definition seems good for agnosticism but not for atheism.

as an atheist if you don't make the claims ''God is unlikely" or "God doesn't exist" it doesn't seem to me like you are an atheist,it seems to me like you are an agnostic,why not just say ''i am an agnostic"?

there is already a word for someone who lacks a belief in God and just isn't convinced and doesn't make any claims about the truth...it's called agnosticism,that's not atheism,that's agnosticism.

since there is already a word for that,why not use that word?

2:That doesn't seem to define atheism,that seems to be ''an autobiographical comment on one's personal psychology" as William Lane Craig would say.

from what i've noticed most atheists who use this definition are just trying to hide from the burden of proof,while later on,after defining atheism,they make claims like:''God is unlikely''

or "God doesn't exist''

if an atheist is not someone who claims there is no God,then what is?

what is the word for a person with such a claim if not ''atheist"?

Also:
There are professional atheist philosophers who tell us that atheism is the belief that there is no God

And we also have sources like the stanford encyclopedia of philosophy which tell us that atheism is the belief that there is no God