I’m not a fan of theirs, but they are said to have won only a plurality of votes in the last elections, held over 15 years ago, after which they consolidated power. So most people in Gaza didn’t vote for them back then, and the vast majority there now didn’t vote for them, either.
The Palestinian Authority followed the same voting system when Yasir Arafat and Mahmoud Abbas were elected. “One man, one vote, one time.”