It does: like an overfit (verb) model, Deep Blue and Jeopardy Watson don't generalize well to other problems.

Overfitting concerns itself with generalization to out of training data on the same task.

I think the term you are looking for is that it's too domain-specific. Or "it uses too much feature engineering and domain-specific engineering."

I see quotes to use it as an analogy. I'm not claiming that their algorithm over fits. It is just another way of saying the system is too specific and optimized to chess to be generalizable.