Atheists know there is a God
This argument is made against atheists. Theists claim that the existence of God is so axiomatic, that nobody can deny God. Often times rather than actually providing proof or valid argument for their God, they resort to claiming that the evidence is all around us. Or they claim that God somehow is either a part of everyone or since God created our souls/life we, therefore, already know him. Based on that assumption, theists claim that all atheists just "pretend" not to believe in God and paint atheists as hypocrites.
Of course, this argument is utter nonsense.
For the most part, it is not axiomatic, obvious, or self-evident that there is a God (feel free to further explore this site to see why). Rather, the theist who makes this argument is completely blinded by their own faith in their own personal beliefs that they have deluded themselves into thinking that their beliefs are universally shared and accepted internally by every human on earth. The reason why this is delusional is because there is no way to know what every human thinks or believes, and thus this argument depends on loads of wishful thinking.
It is also a terrible attempt to claim that the person knows the atheist better than the atheist. Just as a person could easily spot the ludicrousness in the statement that they know that universal invisible sky pixies exist (and they just pretend that they don't believe), a theist should know better than to obnoxiously assert that atheists pretend not to believe in their particular god.
Most of the time, the theist who uses this argument does not have a leg to stand on. Therefore, the theist retreats to wishful thinking.