Overland crossing points are also commonly called ports of entry. Obviously Greta should have sailed to a port in Israel or Egypt, and transshipped her aid package from there to the nearest border crossing into Gaza. But that would have been a waste of all those donation dollars. The whole point of her boat ride was to make a big production of flouting the blockade, and getting stopped by Israel. There was never even any meaningful amount of aid in play.
It was a scam, my dude. A thunbergskam, if you will.