I regard the brain as a computer which will stop working when its components fail. There is no heaven or afterlife for broken down computers; that is a fairy story for people afraid of the dark.That is perfectly fine for him to believe. Intelligent people for millennia have disagreed on the existence of God. But what Dr. Hawking is doing is different; by calling religious belief a "fairy story for people afraid of the dark," he's essentially calling believers childish, perhaps even stupid.
What's worse is that he is still a well-respected and beloved figure, not just by scientists but by everybody. It's not an exaggeration to say Stephen Hawking is probably as popular as Albert Einstein. Most likely, Einstein didn't believe in God, either -- at least not in the same way that most Americans believe in a personal God. But, Einstein didn't go around telling people how childish they were; Hawking is. Why?
It's easy to speculate, but nobody except Dr. Hawking knows the answer to this question. It is worth noting, however, that some famous scientists, toward the end of their careers, behave in ways that make them look foolish. For instance, Linus Pauling, who won the 1954 Nobel Prize in Chemistry, spent the latter half of his life peddling the idea that vitamin C could treat both cancer and the common cold.
One wonders if Dr. Hawking is on a similar path. Perhaps he is simply scratching a philosophical itch. Or, at the age of 69 and recently recovering from a serious illness, perhaps he is confronting his own mortality -- and lashing out at the very universe he has so beautifully described in his books. We'll never know.
But, it would be a shame if Dr. Hawking, instead of being remembered for his earth-shattering contributions to physics, is remembered as the man who spent the twilight years of his life insulting other people. Einstein would likely not approve.