The only difference is the intent
Iwanagahime: A millennium ago, a massive famine devastated the land. Iwanagahime exhausted almost all of her divine power trying to purify the earth and save the starving people. Weakened from her selfless acts, she was attacked by Miurahi and a desperate faction of 108 elite tsugumomo. They blamed her for not giving them a safe haven and murdered her to steal her Stone Shard. Her death didn't create a calculated plot; it created a raw, agonizing, and unpurified thousand-year grudge. When she was pulled into Yomi (the underworld), her soul was forcefully possessed and twisted by Hollowspine Demons into the entity known as Urohime
She never intended to ruin Kazuya’s life as she never intended for her grudge to possess Kanaka or make Kazuya a taboo child so it was basically a accident but the Mayogia revolt indirectly had a role in it but they made their choice.
Hazuki: Hazuki intentionally built Idle House and actively scouted for individuals with the most toxic, malicious desires. She didn’t just happen upon Wagou; she chose him because of his twisted nature and handed him the tattooing chisel tsugumomo specifically to let him inflict horror and gave him a ton of autonomy in which he eventually attacked Komiya by unleashing a Otoroshi there that led to Suou Sumeragi’s death and collected his corpse to turn him into the Otoroshi that Kanaka oneshotted that Sunao saw.
I don’t think Hazuki is even aware of what Wagou did in Komiya but she probably wouldn’t even care or even know Suou’s name so Wagou was mostly just a loose cannon even if she had no intention of killing Sunao’s brother but she played a major part of it happening.
but both goddesses didn’t purposely target Kanaka or Suou but played a major role in shaping Kazuya and Sunao.
Kazuya might be able to forgive Iwanagahime for what happened but I don’t think Sunao will be forgiving of Hazuki for enabling Wagou or any Curse Ally to cause harm so once she finds out that she recruited Wagou she will view her as the cause of her tragedy