One can indeed argue that Hamas started this massacre with the October 12 attack. But Israel is actively imperialist, willfully genociding Palestinians and annexing territory from their neighbours.

That's nothing like Ukraine at all. And not the behavior of a victim.

And the actual longer term conflict started in 1947 when Palestine and the surrounding countries plain refused to agree to a UN resolution, again due to pseudo-religious nonsense.

There were various reasons to reject the first UN resolution, none of which were "pseudo-religious":

• The Arab states claimed that the UN did not have the authority to set the borders here and split the territory. They wanted the ICJ to rule on that, but were denied by the UN.
• Various territories assigned to Israel contained a majority Arab population, which did not want to become part of a Jewish state.
• Handing lands with Jewish majorities in them to a new Jewish state was seen as contentious anyway, since a lot of those areas only became majority Jewish after Zionist terrorist movements (which even the UN declared terrorist btw) used terror attacks to ethnically cleanse the area. It was seen as rewarding terrorism (the irony being that terrorism from Hamas is now used to deny Palestinian statehood).
• There were significant worries that Israel would not stick to the borders and expand further, which ultimately happened when Israel unilaterally declared independence and immediately laid claims to neighbouring lands, anticipating they would be attacked (which they were, and they subsequently took some extra land when they won the war).

The whole reason the conflict started in the first place is because Zionist movements started carving out a new Jewish state in already populated lands, supported by pseudo-religious nonsense claims.

Note that all subsequent attempts by the UN to settle the conflict were also violated by Israel, most notably the Oslo accords. The ongoing settler violence on the west bank and in Gaza also hardly makes Israel a "peaceful" democracy.