I hesitate to be a confirmation, but what I can say is that I heard from our partners that incidents, including this one, have occurred, and that humanitarian actors and supplies were either targeted or prevented from entering.
In terms of the reason, again, it's hard for me to speculate, but obviously the intention and the pressure on all parties Hamas may not have wanted alleviated instantly, to keep the pressure on and keep sending the message. One of the reasons specified for their frustration was the cancellation of elections, where they hoped to do well. They were very frustrated with the overall situation with the Palestinian Authority, and the result was the significant conflict.
Hamas, at least in this time frame, became more popular among some Palestinians for being a defender.