Why doesn't Israel bury them?
Americans hate seeing dead bodies on the teevee even for a single instant. That's true even if the dead are enemies they consider to be terrorists. So much of what Israel does is for the benefit of the US audience so I'm mystified why Israel lets the corpses of fighters rot where they fell.
Israel has its own agenda as well. I mean they could have fougt and decisively win ages ago, but keeping the the opposition "alive" grants then funding. Its not like every decision Israel makes is for the U.S' benefit.
That's what it may seem like, but it's not usually the case.