While that maybe true, splitting an island into 2 and killing the deity protecting it seems like a good argument
Except the deity was the first to invade said island, breaking out a war that was ended by Raiden.
There would be no Watatsumi if the twin gods didn't allowed them to stay in the first place and for the damage the serpent did in Yashiori, they didn't extend the punishment to the whole people of Watatsumi, so that's twice the Raiden Shogun allowed them to live in Inazuma. Three even, if we considered they kept the war going during the Vision Hunt Decree.
Except the deity was the first to invade said island, breaking out a war that was ended by Raiden.
There would be no Watatsumi if the twin gods didn't allowed them to stay in the first place and for the damage the serpent did in Yashiori, they didn't extend the punishment to the whole people of Watatsumi, so that's twice the Raiden Shogun allowed them to live in Inazuma. Three even, if we considered they kept the war going during the Vision Hunt Decree.
But in the upcoming patch we will learn that the serpent was FORCED to attack Inazuma by higher forces, AKA Celestia.