[Serious] Atheist Dogma

[Mr.wizard]

Lack of belief or unbelief is a synonym for disbelief, they are not two different definitions. 

This is a little fuzzy. It's another case where clarifying definitions is good.

Merriam Webster says that 

Definition of disbelief

: the act of disbelieving : mental rejection of something as untrue

while

Definition of unbelief

: incredulity or skepticism especially in matters of religious faith

To me these are different. The former means active rejection, the latter is skepticism or mere failure to accept. At the same time, M-W lists them as synonyms. So we can use whatever definition you prefer. 

You want to limit the definition of "atheism" to simple lack. David Mitchell uses it to mean an active denial. When you are emperor, you can put him in jail. 

I didn't know you were saying about atheism, this is what you said "I agree with you that atheism defined as lack and only lack is not a good position. I don't think it's possible in an adult human with a functioning brain."

Yep, that's what I said. 

Atheism is a lack, but it is not a lack in the way that stones lack belief. It is a lack based on and maintained by other beliefs. It is not a simple pure nothing-but lack, which has no need to be defended. It is a position maintained about certain truth claims, made possible by different truth claims.

Merriam Webster also lists non-belief, unbelief, and disbelief as synonyms. 

Mitchell portrays atheism as knowing there are know gods, that's a misrepresentation of atheism. He can use Atheism to mean bananas for all I care but he is misrepresenting the concept.

Lack of belief in something does not require belief in something else. For instance if you say to me god created the stars, I could reject the claim based simply on the lack of evidence, I don't need to believe in an alternative explanation for the stars.