I have heard many an atheist claim that is the case. Indeed I am sometimes guilty of using that word to describe myself in place of atheist. Occasionally one wants to minimize the impact of their beliefs in a religious world. Agnostic means without knowledge. Atheism means without a god or religion.
I do know that I don't believe in an Abrahamic god, heaven, hell, original sin or supernatural miracles. However, I do not know that death means the end of consciousness. In that sense I am agnostic. It may well be the end of consciousness and I am OK with that. However, I look around at a universe that recycles itself. The body of a dead animal feeds a myriad of other organisms and is thus recycled. Our solar system was born from the death of a star. Our universe may have spawned off of another universe ( Multiverse Theory). It seems like an endless cycle. Ultimately none of us knows as we have not returned from the dead. I suppose it comes down to semantics and how you interpret the word.
Oh God said to Abraham, "Kill me a son"
Abe says, "Man, you must be puttin' me on"
God say, "No." Abe say, "What ?"
God say, "You can do what you want Abe, but
The next time you see me comin' you better run"
Well Abe says, "Where do you want this killin' done ?"
God says. "Out on Highway 61".
Is the word agnostic a cop out?
OK, let me put this on you. As an atheist I cannot tell you that I know for a fact that there is no god. It is very probable that there is no god, but if I make an exact claim that no gods exist I have put the burden of proof upon myself. This is what theists do when they make god claims. They put the burden of proof upon themselves by making that claim.
Agnostic is simply a word. What the agnostic is saying is that in all probability there is no god but he doesn't know for sure. There is no evidence of any gods and never has been. This makes the agnostic exactly correct. If you call yourself an atheist you should have the same viewpoint to avoid a burden of proof.