Mono-white Aggro floods the board with cheap creatures (Thraben Inspector, Novice Inspector, Lunarch Veteran, Raffine's Informant) backed by Battle Screech tokens, so a sweeper is excellent here. Drown in Sorrow wipes their army of 1- and 2-toughness creatures for three mana while we rebuild with our sacrifice synergies afterward. Nihil Spellbomb is a low-cost way to exile their graveyard and stop Battle Screech's flashback from generating extra bird tokens. Unearth loses value since our own small creatures are exactly what Drown in Sorrow will also be sweeping away, and Accursed Marauder is weaker against a deck with many expendable small bodies to sacrifice.