I don't accept your idea of an aggressor because that would make european colonialism aggressors and would make the US the aggressor against the indians.
But while we are at it, I see that Israel took the west bank by force and intends to keep it. Further, Israel has always wanted the west bank and Jerusalem. Even by your definition, that makes them the aggressors in the 6 day war.
Israel took the West Bank along with the Golan because the strategic depth provided was necessary to insure its survival as a nation. This is defensive, not aggressive, in nature. Without the Arab seige Israel would not have taken those territories.
The European colonial experience was aggressive as well. The US expansion is a mix of both defensive and aggressive.