That is not what "hacked" means. If they had really hacked Google their servers and proxied all searches through a system of theirs without letting the users know it would not have been "apparent" yet Google was hacked in the correct sense of the definition.
They were defaced which was directly apparent to users - not hacked. At all.
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.