Gazans were in an open air prison prior to October. Israel bombed Gaza pretty regularly, and Hamas said that their October attack was in retaliation.

Hamas explained all this in an interview with the New Yorker. Gazans tried peaceful unarmed protest and were shot by the IDF. They asked the international community for help but the Israeli government labeled it “diplomatic terrorism” and sanctioned Palestinians. What choice did they have left but to fight when nonviolent resistance got nowhere?