[MichaelSalib]

Can they control what goes through those borders? Can they control what happens in the airspace above their territory? Do they have a seat at the UN?

The answer is no to all 3.

Question: if I want to fly into Gaza, whose permission do I need? Hamas' permission is clearly insufficient: the IDF will shoot down any plane landing there. So they're not at all an independent state.

[maratd]

Being under embargo/blockade is not the same as having no state. When the US did the same to Cuba 50 years ago, Cuba didn't magically disappear or become invalid.

Do you know why the US did that to Cuba? They were smuggling missiles in. See a pattern there?

[MichaelSalib]

If you have no control of what enters or leaves your territory, no control over the air above your head or the electromagnetic spectrum, and no international passports, I don't see how you can be a state.

The whole point of a state is that it has some effective control.

[gadders]

You realise Gaza has a border with Egypt as well, right? You can't blame Israel for keeping that one closed.