Why do atheists need to build a monument? They are not celebrating anything. They are merely stating that they do not believe in God. You assume something has to take God place, it does not. You probably don't believe in lots of things, do you build monuments to everything you don't believe in? C'mon, move off a 6th grade argument.
I wholly agree with you. Atheists can't have a monument or a bumper sticker. They simply lack something others don't lack. It does not deserve a celebration.