Why doesn't underclocking count for game playability??

[alexybubble]

Looking at the compatibility list, two of the 3 games listed as broken seem to able to boot with underclocking, 3 of the 5 games listed as Intro/Menu seem to be playable with underclocking, and there are probably a few others in the other categories. Why are these games not considered playable, since having other settings be mandatory doesn't seem to exclude a game from playability?