Its charter says so, and the continual deadly rocket fire backs this up. So, the border is closed. Try to break through the border, and you get shot. Really pretty simple. There are no exceptions for age or intent. When Hamas knocks off it juvenile nonsense, the border policy will get relaxed. It was not all that long ago the 40,000 Gazans left for work every day in Israel. With better leadership, this can happen again.
U.S. weighs sanctioning Russia as well as China in cyber attacks (Reuters)
from the article: IDF denies killing Palestinian teen on Gaza border