1. Gaza is occupied under international law per the International Court of Justice.
"28. Although it no longer maintains a military presence in Gaza, Israel has not only shown the ability to conduct incursions into Gaza at will, but also expressly reserved the right to do so as required by military necessity. This consideration is potentially significant considering that there is support in international case law for the conclusion that it is not a prerequisite that a State maintain continuous presence in a territory in order to qualify as an occupying power. In particular, the ICTY has held that the law of occupation would also apply to areas where a state possesses “the capacity to send troops within a reasonable time to make the authority of the occupying power felt.” In this respect, it is also noted that the geographic proximity of the Gaza Strip to Israel potentially facilitates the ability of Israel to exercise effective control over the territory, despite the lack of a continuous military presence.
29. Overall, there is a reasonable basis upon which to conclude that
Israel continues to be an occupying power in Gaza despite the 2005 disengagement. The Office has therefore proceeded on the basis that the situation in Gaza can be considered within the framework of an international armed conflict in view of the continuing military occupation by Israel."
Opinio Juris » Blog Archive The OTP Concludes Israel Is Still Occupying Gaza - Opinio Juris
2. The Occupying Power is responsible for the welfare of the people under occupation, per
"Under Article 43 of the Hague Regulations, an occupying power must restore and maintain public order and civil life,
including public welfare, in an occupied territory.......... "
http://www.hpcrresearch.org/sites/default/files/publications/sassoli.pdf