Fantastic movie, I especially liked the body horror aspect they used with the ETs, the way they moved and the huge long limbs etc.
Spoiler time though, I reckon it was all the parasites. The only way they can survive and propagate is by assimilating new hosts, that's why there were a bunch of different ET species but they all looked uniform and they were all sexless too because the bodies are just vessels for the parasite, they have no need to reproduce. Also why the ETs didn't care she ganked those other ETs, the parasites escaped and there were plenty of new hosts to be had, it was only when she tried to crush the parasite that they got angry.
And the end bit where the ETs are talking about what to do with her and that ET's throat is vibrating, it's because the parasites are discussing what to do with her and not the hosts. The tall classic ETs are powerful telekenetics so it would stand to reason they're equally powerful telepathics too so they wouldn't need to talk vocally.
So I reckon the parasites cooked up the "perfect world" shown at the end to keep the humans minds docile while the parasites piloted their bodies around, assimilating new species.
Hamas was also left to run amok for 5 hours and at the end of that were able to cross back over the border with hostages.
How on earth is one of the worlds most powerful militaries caught with it's pants down that badly and how were they not able to organize some kind of a response in 5 hours?
At the very least you'd have expected them to ambush them on the way out and rescue the hostages. They have fleets of drones for pete's sake, they could have taken out every single one of those terrorists with drones to spare.
It makes no sense whatsoever, unless of course they let it happen as a casus belli to once and for all deal with the Palestinian problem.