Well, they did it, because they observed that leaving boost enabled was misleading and hence a big mistake. I agree, for the most part.
The problem with boost is, that for benchmarking it will always give better results, than for actual gaming, because benchmarks usually only run a few minutes at best. A card takes a certain time to get temperature soaked, and runs faster, until that point is reached.
Benchmarking with the goal of obtaining results that have real world relevance requires that boosts are disabled, or each benchmark is run 10 minutes, before a measurement is made. The latter is too time-consuming for most people to do.
Actually, disabling boost should help the better card, as boost mostly boosts average FPS by increasing FPS when they are already high, but has trouble coping, when FPS are dropping during more complex scenes.