Given they targeted observation posts and monitoring cameras first, I suspect they don't want witnesses observing war crimes. Local witnesses are outright killed or smeared with accusations of belonging to militant groups, as it's being done to journalists in Gaza. They just put targets on the backs of the few surviving journalists that are still documenting the siege of northern Gaza. See: https://www.aljazeera.com/program/inside-story/2024/10/24/wh...

That trick is harder to pull when the witnesses are external UN observers.