For the same reasons, Hamas has to punish Israel for any aid, benefit, or mercy to the people of Gaza. This attack came after Israel's work permit program, which was supposed to let Palestinians bring home money. Hamas used it for intel on Israeli targets (specifically on Israelis willing to hire Palestinians). That program isn't going to happen again. We can be certain Hamas considers hijacking aid shipments a high priority, to keep them from their population and force Israel to choose between dead Palestinian civilians and supplying their enemies.
This has been going on since Israel first occupied the territories. They tried to build functional neighborhoods and civic structures for their new charges, but the Arab world was furious about moving people out of the refugee camps to anywhere but where they or their ancestors had come from.