Murdering and kidnapping civilians with the purpose of enacting their political goals does fit the label of terrorism. Then again, Israel does also murder and kidnap Palestinian civilians (and I mean kidnaps, because they don’t have the legal grounds to imprison people at the West Bank) for the sake of their political goals, and they don’t get called terrorists. So I call both Hamas and Israel terrorists, but a good general corollary is that there’s always political motivation behind someone using or not using that label.