Atheists generally lump all religions together. To an atheist it makes as much sense to worship Ra or Dispator as it does to worship Christ or Allah. It also tends to confound Religious types who will agree with the atheist, except when it comes to their own God.
The basic difference between an atheist and a religious person is that the God fearing person believes in one specific God and rejects all the rest, while the atheist simply rejects them all.
Nicely put.