Why did Israel feel SOOOO threatened by the aid convoy that they resorted to killing?

this isn't the first time Israel does something like this in the 2003 war with Lebanon they killed over 20 UN peace keeping soldiers now they storm an aid boat full of activists and parliament members from EU and NATO countries which was on international waters and why not use rubber bullets instead of shooting up a crowd of high-profiles nothing would justifies such an act Israel should not get away with it this time it is our ally but what if your son shoots up a liquor store would you let him get away with it and continue on to shoot up a bank ? NO VITO THIS TIME