Israel doesn't prevent humanitarian aid. It just makes sure that are no weapons there and then pass it by land. But let me ask you something - if you were being fired upon constantly by your neighbor, and then he tells you you must let him pass through your yard to go to the supermarket, will you let him?
Islamic State militants blow up ancient Arch of Triumph in Palmyra (Reuters)
from the article: Netanyahu: Israel will not allow flotilla to breach Gaza naval blockade