I think there's a distinction between worst-case and adversarial behavior.

For some types of problems, identifying worst-case behavior is straightforward. For example, in a hash table lookup the worst-case is when all keys hash to the same value. To me, it seems like overkill to think in terms of an intelligent adversary in that case.

But in the problem described here, the worst-case is harder to construct. Especially while exploring the solution space given that slight tweaks to the solution can significantly change the nature of the worst-case. Thinking of it as adversarial implies thinking in terms of algorithms that dynamically produce the worst-case rather than trying to just identify a static worst-case that is specific to one solution. I can imagine that approach significantly speeding up the search for more optimal solutions.