If he had known that a creationist would be quoting him he might have been more careful with his language. If I recall rightly, just a sentence or two later he talks about different interpretations rather than different theories, and the latter is certainly closer to the reality of the situation.
Evolution describes something which happened in the history of the earth, and it is not intrinsically either theistis or atheistic; it is just a description of what happened. What can be theistic or atheistic is the interpretation which gets put upon what happened.
Would I expect the Pope, or the Archbishop of Canterbury, to endorse an atheistic interpretation of Evolution? No, not really. But neither would I expect them to debate its truth given the near unanimous scientific consensus in its favour.