Well, William L. Rowe, who wrote this Routledge entry, prefers to use the term non-theist to describe logical positivism, but for example, but the impression I got from Britannica's entry on atheism is that they prefers to label them atheist. On the other hand, the Britannica considers "practical atheism" to be a misleading term, and prefers to not call them atheists because their position isn't ontological.