Um, the IDF has been killing Palestinian civilians en-mass since the start of the war. Using 2000lbs bombs in civilian areas kills civilians.

I think your imagination of how it looks like if a high tech military wants to kill civilians "en-mass" in a highly dense area like Gaza is severely lacking. And I'm not blaming you really, that's not a nice thing to think about. But it does cloud your judgment.

What they are actually doing, instead of committing genocide, is prioritising winning the war over causing civilian casualties on the enemy side. Nearly every army does that in a war. We could say to Hamas that this is the cost of starting a war, but that would be of course pointless, since they care even less about civilian casualities than IDF. They prioritize causing global outrage against Israel over their own civilians. Some evidence suggests that's what they're aiming for.

Strawman: IDF is committing genocide.

Steelman: Hamas tries to maximize civilian casualties to generate international outrage.

Truth is probably somewhere between these extremes. I'm leaning towards the steelman argument but not heavily.

Obviously it is not committing a genocide. They're fighting a city block war inside a highly dense area against an enemy who uses its own civilians as both shields and fodder for creating global rage.