Yes it was. Let's not quibble.
They were defaced which was directly apparent to users - not hacked. At all.
"a hacker is someone who seeks and exploits weaknesses in a computer system or computer network" ( http://en.wikipedia.org/wiki/Hacker_(computer_security) )
Being hacked means a hacker has found and exploited a weakness in a computer system or network. Saying that Google Palestine was hacked is false because no exploit in a computer system or computer network OF Google Palestine was found nor exploited.