I have no idea if the current Gaza denizens are related to the ancient occupants but they do seem to have a few things in common if this is accurate:
“The Philistines were an aggressive, warmongering people who occupied territory southwest of Israel between the Mediterranean Sea and the Jordan River. The name “Philistine” comes from the Hebrew word Philistia, and the Greek rendering of the name, palaistinei, gives us the modern name “Palestine.” The Philistines are first recorded in Scripture in the Table of Nations, a list of the patriarchal founders of seventy nations descended from Noah (Genesis 10:14).
It is thought that the Philistines originated in Caphtor, the Hebrew name for the island of Crete and the whole Aegean region (Amos 9:7; Jeremiah 47:4). For unknown reasons, they migrated from that region to the Mediterranean coast near Gaza. Because of their maritime history, the Philistines are often associated with the “Sea Peoples.” The Bible records that the Philistines had contact with both Abraham and Isaac as early as 2000 B.C.”
https://www.gotquestions.org/Philistines.html
They just cheered over deaths of a thousand civilians and they have no idea why nobody likes them.