I don't think its that complex. Group A gave permission for Group C to move into Group B's place. Group C decided to get a bunch of Group N's support to start the liquidation of Group B.
Decades of Group B, playing to the "Rules Based Order" crowd resulting in no end to the violence Group C was doing to Group B resulted in Group B being more and more okay with countering violence with armed resistance.
You're not wrong, but it's not insane to say that Hamas is not an innocent group. That's all I'm saying - it's just as much a crime to ignore blatant terrorism.