> The Palestinians agreed that all imports of goods are diverted to the Kerem Shalom border crossing, because Israel threatened to exclude Gaza from the customs union out of concern about the implementation of the Paris Protocol.
> Israel tightly limits the flow of concrete, cement, iron bars and other materials into Gaza, as “dual use” items that could have a military purpose if they were seized by Hamas to rebuild tunnels used to launch attacks.
> That means few homes have been rebuilt despite international pledges of billions for reconstruction. Rather than wait to rebuild permanent homes, some relief agencies have decided to build temporary structures with materials they can get.
> The adverse effect of dual-use restrictions is mostly felt in manufacturing, ICT and agriculture. The agriculture sector contributes significantly to Palestinian food security; however, the dual use restrictions have lowered the concentration of active chemicals in fertilizers making them less effective and lowering land productivity to half of that in Jordan and only 43 percent of the yield in Israel.
> For example, the restriction on ‘communications equipment, communications supporting equipment, equipment containing communication functions’, limits access to modern manufacturing production lines, spare parts, medical equipment and home appliances. It has also stood in the way of developing the Palestinian ICT sector and created a large technological gap with neighboring countries.
Everything's dual-use, then, including basic necessities.
Food - could be used to feed combatants!
Medicine - could be used to treat combatants!
Consider the possibility that "you're not allowed to build houses for your families because we won't let the materials in" potentially inflames more terrorism than it stops.
edit: Regarding your edit, "Edit: Basic necessities to sustain life - food, water, medicines are allowed."
Shelter is considered one of the basic necessities.
> If you had a bad neighbor, you would do the same.
If I had a bad neighbor, and I walled them in and forbade them from buying concrete and fertilizer, the police would likely intervene in their favor.
https://en.wikipedia.org/wiki/Rafah_Border_Crossing
> The Palestinians agreed that all imports of goods are diverted to the Kerem Shalom border crossing, because Israel threatened to exclude Gaza from the customs union out of concern about the implementation of the Paris Protocol.