Further from your link ..
According to the organization, this was due to the trucks being intercepted either peacefully by hungry people or forcefully by armed actors during transit in Gaza. This accounts for 88% of all trucks...
... Olga Cherevko from the UN Office for the Coordination of Humanitarian Affairs clarifies to The Times of Israel that the vast majority of looting is being carried out by hungry Gazans, not by armed gangs.
The long-standing restrictions on the entry of aid have created an unpredictable environment where there is a lack of confidence by the communities that aid will reach them, she says.
This has resulted in many of our convoys offloaded directly by starving, desperate people as they continue to face deep levels of hunger and are struggling to feed their families, the UN staffer continues..."
But there are gangs, maybe more starving people though.
Israels support for clans in Gaza puts tribal strongman in spotlight
https://www.washingtonpost.com/world/2025/08/03/israel-gaza-clans-abu-shabab/
Updated August 3, 2025
"JERUSALEM Yasser Abu Shabab is all over Israeli news and Palestinian social media.
He describes himself as a humanitarian and a liberator. International aid workers allege he was behind the systematic looting of aid entering the Gaza Strip last fall.
Some Gazans including analysts, residents and members of his own tribe say he is a gang leader aligned with the Israeli military. Yasser Abu Shabab doesnt represent us. He only represents himself, said Adel al-Tarabin, a leader in the Bedouin Tarabin tribe to which Abu Shabab belongs. He went on to describe him as a looter and a bandit.
... But the base that the militia leader said he has set up is in a part of southeastern Gaza under the control of the Israel Defense Forces. And in recent months, Israeli forces have refrained from interfering when Abu Shabab and his men, armed with AK-47s, patrolled a central artery in the area and stopped U.N. and Red Cross vehicles at makeshift checkpoints, according to several aid workers in Gaza..."