Izzet Aggro's board is almost entirely 1-3 toughness creatures (Monastery Swiftspear, Pompous Battlemage, Emberheart Challenger), so Withering Curse's -2/-2 is a clean one-sided sweep that swings the race in your favor. Unlicensed Hearse blocks profitably and grows while denying any graveyard recursion from Stormchaser's Talent's level 2 ability. Badgermole Cub is too fragile to survive their burn-heavy removal suite (Burst Lightning, Reckless Rage) and doesn't impact the race enough, while Culling Ritual is often too slow against their fast curve. Prioritize Fatal Push and Abrupt Decay on their early creatures to stay ahead on tempo before Screaming Nemesis punishes incidental damage-based answers.