Judging by the report it seems that these hackers ARE palestinian. One could easily conclude that Palestinians are likely to be sympathetic to the Palestinian cause.
If they were sampled evenly from world population, it would be what you would expect.
Agreed, but that sample wouldn't get many people who shout out their opinion without being asked by it (a majority may support Palestine, but far less actively make their voices heard about it, on either side)
There are a lot of "hacktivist" groups based in Palestine, Iran, Egypt, and Syria.