Goblins is an extremely fast go-wide aggro deck, so you need cheap removal and a way to stabilize against a swarm of small creatures. Swords to Plowshares answers Goblin Piledriver or Siege-Gang Commander's tokens, while Thrashing Wumpus can wipe their board of 1/1 and 2/2 Goblin tokens over a couple of activations. Arcane Denial is too slow and gives them extra cards to rebuild their board, and Infernal Contract's life cost is dangerous against a deck this aggressive. Prioritize surviving to turn 4-5 to assemble your combo.