The last election in Gaza was held in 2006. The electorate has not been given, in the intervening 17 years, a chance to voice its will on the matter.Also, maybe the Palestinians shouldn't have elected a TERROR GROUP to run their prospective country...
Demographics can change a bit in 17 years.
Also, the opposing party, Fatah, was in a bit of a nepotistic, corrupt rut when they were voted out. The populace was in much the same frame of mind as you were in 2016, when you voted for Donald Trump and then danced around about it for several months, rubbing it in the face of whoever expressed any reservations about the incoming administration.