Is it logical for atheists to put up holiday displays?

I noticed in the news this morning that in Santa Monica California some self-professed Atheists had secured space to put up a scene promoting their beliefs, much like the Christians are in the habit of doing. What is the point of spending time and money promoting beliefs, for or against God, in a universe that is said to exist without any objective moral standards or purpose? If you think Christianity or some other religion is bad or Atheism is good, haven't you just affirmed everything you deny by being Atheist?