Maybe this thread should be titled "What do atheists believe?".
Some of them apparently believe they lack belief, although this belief doesn't really make sense to anyone else. They are apparently unable to believe in the existence of a god, which translates as "lacking belief in god", and they believe this lack of belief is some kind of strategic point of view, rather than a misuse of language.
The misuse and misdirection becomes apparent when the subject of infants, who presumably lack the ability to have beliefs at all, is presented as some kind of supporting argument for their belief in their lack of belief.
Or maybe the people who think they're atheists and not just people who disgree with religious teaching, for all the "right" reasons, can fill in the blanks.
And of course, all you need to do to understand the subject is read the Bible, right?
No need to question the possibility that the "lack" is of understanding of the subject. Everyone who claims they're an atheist knows all about the subject they find they can only form a "lack" of belief in, and so they have something to believe.
I believe what they mean to say is: they lack information about the subject of the existence of a god, therefore they are unable to form a definite belief or opinion except for the one about believing firmly in their lack of belief. They also, being mostly westerners, believe that a subject has to be believed "in", but that doesn't really stand up either. I don't believe in gravity, I believe gravity exists. I have no real concept of belief "in" gravity, because it doesn't make a lot of sense to me. It isn't like joining a club whose members believe "in" this or that and congratulate each other for making the right choice, for god's sake.
But, let's believe things.
The misuse and the misdirection is in that either one or both sides are convinced they know what the other side means by "belief in God."
As such, theists are not justified to criticize atheists, and atheists are not justified to crticize theists.