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I think that Israel is committing genocide because it's not killing members of Hamas, but mostly civilians. If it was only between them and Hamas it could be called war, but it's not.
Though, alledgely Hamas also targeted civilians when they attacked Israel back last year. So I am not sure to what extent they could called to be a guerrilla or some kind of irregular fighting parting seeking to reclaim territory from an invader.
If both sides only targeted combatants, then this would be a very different situation and it would be easier to call this a regular war, but it is not.
Each side alledges the other is targeting and purposely killing innocent people, for the sake of a political and territorial aim, that is terrorism.
Anyone seeking for the killing of non-combatants for the pursue of a political objective is a terrorist.
Denpending whom you ask, this is a war between a legitimate faction versus a terrorist one, but others will say this is rather a war between terrorist factions.