Some of the language used is horrific and dehumanizing. I do not support it.
A couple of points, though.
1. It matters who is speaking. A random veteran spewing vile hatred does not suggest a legally sound argument for the intent necessary to prove genocide. Nor does any "former" member of random government agency. If the charge of genocide is against the STATE of Israel, then you would have to prove a systematic, deliberate intent by those in the current government of the STATE.
2. Some of those statements are reactionary, and understandably so, as the people and government of Israel were actively fighting in the first few days after the invasion and coming to understand the scale of the atrocities committed. Still not okay, and not something I would support, but understandable and not evidence of intent to commit genocide.
3. The Jewish, or at least my understanding of the Jewish, reference to Amalek is WAY more complicated than a simple and clear intent to commit genocide, especially as a legal argument. Yeah, I know that sounds like a shitty excuse, and yeah, I call people out when they try to excuse other religious terminology like "intifada" and "jihad". Still. Bibi's audience was a Jewish audience in that clip, and they would know the richer definition, especially the appeal to remember.
4. As you brought up, the actions do not suggest an intent.