Clearly the absolute number of casualties (not even civilian casualties in this case, that is allegedly more like 15k) is not sufficient on its own to define a genocide.
Given this historical context, we don’t need to “whatabout” with the Allies. Surely we can agree that we do not want a repeat of WWII.
In terms of whether Israel’s actions constitute genocide, we have yet to find out. Are they grossly disproportionate compared to Oct 7, and appalling in terms of their destruction of civilian life and property? I believe yes, and whether or not that is “genocide” is, to me, somewhat besides the point. Making it stop NOW is the point!