" This ultimate reality supports and nourishes humanity and all other living beings. Those who have perceived this ultimate reality inherent in their own lives truly know themselves; they are Buddhas. "
Well, the only point I was trying to make is that spirituality, in any form, is not consistent with atheism. Your mentioning of "ultimate reality" above has GOD written all over it.
Now one can always object to any statement about God, and I can already hear you saying that the ultimate reality of Buddhism has nothing to do with the human-like Christian God. But let me anticipate your reply and explain what the real problem is.
When one uses a word such as 'atheism', one necessarily invokes the concept of a reality that is indifferent to the human condition - a careless universe. The atheist's world is not only a god-less world, it's a world where human problems of any kind, including the very real possibility of eternal annihilation, can only be solved by humans themselves. The atheist's universe does not respond to human actions; to a careless universe compassion is a completely meaningless term. The atheist can't possibly get anything from the universe other than by directly controlling it through the use of sheer physical force - a rather hopeless proposition, I might add.
It is my impression that Buddhists do not believe in a careless universe, that they actually believe in an 'ultimate reality' which watches our every single action and our every single thought, and rewards and punishes us accordingly. If that is the case, then Buddhists do believe in God after all, only perhaps they don't realize it, just like atheists don't realize how essentially flawed their world view is.
So, as with most issues, this seems to me to be just a matter of agreeing on what a particular word means.