We should stop using this term terror/terrorist, it's lost any meaning. If Hamas are terrorists because they're terrorizing Israeli population then so are Israelis' IDF or whatever force kills other country's population. And the list extends beyond that. To paint a resisting force/army as terrorists is just charged language to emotionally manipulate and pollute discourse. It would be more useful to put in balance what each side is fighting for.
Terrorism has a simple definition: using force against civilian life to further ones goals.
Target a music festival with no military value: terrorism.
Blow up a building because hamas has a tunnel under there: not terrorism. If the military value gained is disproportionate to the civilian cost, it is a war crime. But still not terrorism.