Melinda at Stand to Reason points out several differences between “atheist” holiday displays (particularly that in Olympia, Washington) and religious ones:

[T]he atheist display doesn’t simply express a tenant of their belief, it is actually mocking the religious displays along side it. A nativity and a mennorrah side by side each express something about the religion they represent without denigrating the other. It truly is pluralistic with various religious views of this season expressed. The atheist display, however, denigrates religion and I don’t think that’s in the spirit of these public displays. Let’s have a debate about their claims about religion in the proper setting. But this display is disrespectful in a way the religious ones are not.

Read more at Stand to Reason Blog: Reason’s Greetings.