Gridania's andIshgard's xenophobia is somewhat understandable. Ishgard has heretics that can infiltrate and sabotage.

Gridania has Elemental who, prior to the Calamity, can kill people people for simply cutting down the wrong tree. Outsiders just think the Elementals are this boogieman that Girdania like to talk about, but their real.

With Elementals, they don't care if it's poachers or Garleans that are setting fire to the forest. They'll punish anybody within the vacinity as can be seen here: