Gaza is a part of a separate sovereign state, with which Israel has tense foreign relations and is within its rights to control exports. and they're posting border guards for those exiting it. It's legally no different from inspections that take place at U.S./Mexico border checkpoints.
> They also reserve the "right" to invade Gaza whenever necessary
Source?
> while keeping the population locked in
Source? No country is obligated (except for E.U. member states) to allow the free flow of people without visas. The only thing I've read which might qualify for this claim is naval blockade of the coastline.
> The whole world agrees that it constitutes an occupation
Gaza? Source?
Regarding you request for source on the "right to invade Gaza": > "Israel will continue to control Gaza's coastline and airspace and reserves the right to undertake military operations when necessary. (Art 3.1)." http://www.mfa.gov.il/mfa/foreignpolicy/peace/mfadocuments/p...
This is also evident by the many incursions Israel has made on Gaza. Israel is still firing shells into Gaza with tanks and mortars! https://www.google.com/search?client=safari&rls=en&q=hundred...
Regarding the Israeli control of Gaza being an occupation:
>In January 2012, the spokesperson for the UN Secretary General stated that under resolutions of the Security Council and the General Assembly, the UN still regards Gaza to be part of the Occupied Palestinian Territory.[15]
Israel does not recognize any separate state as having sovereignty over Gaza.
> It's legally no different from inspections that take place at U.S./Mexico border checkpoints.
Last I checked, the US doesn't assert a right to control Mexico's seacoast or airspace, and impose a blockade of shipments into and out of Mexico that do not come through the US.