Hamas is the ruling body, for better or worse, in Gaza. As such they are completely justified in paying their soldiers just like the IDF is being paid for the mass murder of Palestinian civilians. Palestine and Israel are not at war. Palestine is not yet an independent nation (although they are recognized as a sovereign state by 143 countries). This is a one way conflict where Israel is assaulting Gaza. They say they are targeting Hamas but they don't even do BDAs. So they dont know who they are killing and how many. So this is:
a) An assault on the civilian population of Gaza, as an act of collective punishment, which is the Israeli method of operation, and has been for decades. This is further proven by statements by Israeli politicians and officials.
b) Per the IHL's rules of proportionality, Israel's actions amount to war crimes, minimally.
c) Per the terms laid out by the genocide convention, Israel's actions meet the minimum criteria for genocide which are: Killing members of a group, causing deliberate conditions that bring about the physical destruction of a group, causing serious bodily harm to members of a group. And most importantly INTENT as expressed by Yaov Gallant, Itamar Ben Gvir, Smotrich and many other Israeli politicians time and time again. This is what the UN special report lays out and this is why the ICJ also passed the verdict that there is plausible genocide in Gaza. Reviewing the events in Gaza, and taking into account the ICJ verdict and the UN Special report, it is reasonable to conclude that Israel has committed and is continuing to commit genocide in Gaza.