Board Thread:Off Topic/@comment-25396609-20150517000450/@comment-24993958-20150605080950

Except he  did challenge him...indirectly, but he did. Since everyone that eats from the underworld becomes bound to it (and Hades by extension), the compromise wasn't something Hades offered, but forced on all the gods. If Zeus really was the head honcho, he could have completely ignored it, since Persephone spending 6 months in the underworld equals Demetor bringing famine via fall and winter, and it was the famine that made Zeus act in the first place.