You can't move a person who believes in a god but behaves as if there isn't one into the atheist category because they don't fit into it. You'd have to redefine atheism in order to make that work, and you're lacking the necessary degree and scope of influence to do it.
The best you could do with such a deist is to place them into the
apatheist category, which is inhabited by atheists and theists alike (in spite of your incorrect assessment of what does and doesn't constitute theism).
Further, and perhaps most importantly, being a deist doesn't preclude the worship of a god. Some of them are very spiritual people who believe in the importance (and utility) of
affirmative prayer. So your contention that deists necessarily behave as if there is no god is just another example of your considerable (and surprising) ignorance concerning such matters.