Bogles wants to resolve one hexproof threat and pile enchantments onto it, so removal that can hit resolved enchantments is crucial. The extra Thraben Charm can blow up a resolved Ethereal Armor, Ancestral Mask, or Armadillo Cloak. Cutting a Prohibit is fine since our own spells like Ephemerate aren't the priority in this race and Bogles' clock is fast enough that proactive removal matters more than counterspells.