The fact that atheists have formed a megachurch opens up the floor for discussion on what atheists actually believe and where those beliefs, if true, would leave us. Of course, most atheists proclaim that God does not exist and that belief in God leads to violence and superstition, as well as a rejection of science and humanism.
The fundamental problem of atheism lies in the fact that they cannot use science to prove God does not exist. And so it remains a premise of preference, not proof. By forming a church to proclaim their belief they have ironically played the same hand as those Christians they hope to discredit.
Another fundamental problem with atheism is that it cannot effectively answer any why? question. If God does not exist, there is no basis to proclaim any moral imperatives: Whatever you, or the most powerful person in your group, says becomes what is right and moral.
Why are we here? Why did matter come into being? Where are we headed? What is our purpose in life? Atheism has to toss those questions to the side as uninteresting and unimportant because the answers it produces are merely unsupported opinions of non-believers.