The point is, you *can't* "practice atheism", as it has no practices. Prayer is a "practice" of some religions, because religions are complex belief systems involving practices. Atheism is not a belief *system*. It is the lack of a single belief, that in deities. It's no more a belief system than 'aleprechaunism', to coin a term. There's only a term for atheist because theists are prevalent--most people don't believe in leprechauns, but there is no term for 'aleprechaunism'.
Well, I think what he may have mean is the the existance of a god cannot been proved or disproved to any conclusive degree. So an Atheist believes there is no god. I'd agree that you don't pratice atheism, but if you believe in God, you don't have to practice either. That's if you are a follower of a religion. I mean if someone were to believe in a higher power, but didn't worship it in anyway, they couldn't be said to practice anything.
It is one of the things Lini is for, taking the blame. She usualy deserves it even if I don't know how.