Clearly anything Hamas does is justified retaliation

No? They definitely weren’t justified in raping and killing civilians in October 7th. However, as an oppressed and occupied people, they have a permanent casus belli against Israel until the latter starts taking serious steps towards peace, so the act of attacking Israel on October 7th (remember that 66% of the dead were military or security targets; they didn’t just kill some civilians and leave) itself is a legitimate act of resistance.