UBG Reanimator wants to Dark Ritual/Reanimate or Animate Dead a huge threat like Griselbrand or Atraxa, Grand Unifier into play quickly, so Force of Negation is a free counter to stop Reanimate or Animate Dead outright. Surgical Extraction can strip their Griselbrand or Atraxa from the graveyard before they can reanimate it, denying their whole plan. Teferi, Time Raveler doesn't stop a reanimated 7/7+ threat from attacking and dies to their removal suite, and one Daze is cut since their deck doesn't care much about tempo loss when they can simply Dark Ritual through it.