And how do you figure that? Israel withdrew from Gaza while it was still under the PA as an attempt to work at peace. The plan was to do the same in the west bank next. Plan goes through. Hamas was an offshoot of the Muslim brotherhood without any political authority up to that point. Prior it was formed because they were against any peace accords that were occuring at the time. But after Israel withdrew, they almost immediately had an election in which Hamas was given power. And they stuck to their promise of continuing to use violence in order to obtain a state instead of working as part of the peace process. This is when the blockade began.
So are you just saying that due to the fact that Israel exists that Hamas exists? Even that is probably not true. The Muslim brotherhood has a long history prior to Hamas in that region. It is highly likely that even if the whole place had become the state of Palestine, then the same people would do the same shit as they did in Egypt.
So how is it that Hamas existing is the fault of Israel?