My feeling is that the goal of the operation was to permanently shatter the Israeli consensus around security and provoke the Israelis into an invasion of Gaza in an effort to scupper the Trump/Biden/Netanyahu attempt to freeze the status quo into place via normalization

And that they perceived that the best way to do this was by inflicting as much damage on civilians as possible. Although some things are up on the air - I think it’s established they didn’t know about the music festival?