Don and Jim wonder why there are shortages when Israel makes no restriction on imports of food, medicine and humanitarian supplies.
Some times incompetence, inter-Palestinian disputes, but sometimes because the cossing are closed.
Not by Israeli intansigence.
The crossing are a source of essential supplies for Gazans, but also of Jews to kill, and that is a much higher priority for Hamas.
Karni for instance.

The Karni terminal has been attacked several times by Palestinian terrorists since the beginning of the al-Aqsa Intifada, in either mortar attacks or frontal infantry assaults, forcing temporary shut-downs for repairs and enhancement of security procedures. Both Palestinians and Israelis have been killed in these attacks. As a passage point between Israel and the Gaza Strip, the Karni crossing has been used for hostile activities by armed forces from the Palestinian side. Palestinian terrorists have used the Karni terminal to smuggle suicide bombers and explosive belts into Israel. The deadliest suicide attack to come via Karni was the Port of Ashdod bombing.[4][5]

In 2006, the Israeli authorities closed the crossing for over 100 days, after the discovery of vast tunnelling from across the border to underneath the facility, meant to be filled with explosives and detonated.[6] From September 2006 to June 2007, the crossing has been open daily save some brief closures due to Palestinian labour strikes.[7]

When Hamas took over the Gaza Strip, much of the equipment on the Palestinian side was destroyed, and the terminal was closed by the Israeli authorities. The previous operators, who were affiliated with Fatah, have fled to the West Bank. Hamas has offered to bring Fatah back to Karni or hire a Turkish company to operate the Palestinian side, but Israel persistently refused to deal with Hamas, the de facto authority in the Gaza Strip. In June 2007, the UNWRA coordinator commended the IDF on moving humanitarian shipments to the secondary Kerem Shalom and Sufa crossings,