Naturally You can't prove it (yet) for obvious reasons. It is about preventing "a risk of genocide", acording to experts :

UN : https://www.ohchr.org/en/press-releases/2023/11/gaza-un-expe...

Scholars : https://time.com/6334409/is-whats-happening-gaza-genocide-ex...

Historical (Arab) Perspective : https://dawnmena.org/the-historical-roots-of-israels-genocid...