ICJ stands for a lot 🙂
Do you know what Hamas “stands for?” Read their charter.
Also read the Rome Statute definition of genocide. It applies to Hamas on October 7–they murdered, kidnapped, raped, and mutilated because the people they attacked were Jews. In Gaza, Israel has not harmed anyone because they were Gazans or Palestinians or Muslims or any other component of their identity. Hence no genocide.
If you want to show that Israel has committed war crimes by taking insufficient care to protect civilians, there may be a case to be made. But that’s a far cry from what Hamas did on October 7–the deliberate targeting of civilians specifically because they were Jews.