His whole criticism is a bit flawed, since it's uncertain they were civilians. Everyone agrees they were the sons of a local Hamas commander and there are conflicting reports whether they were actually members. The Isreali army certainly claims they were members of Hamas. Besides, the last few minutes of Chomsky's analysis are just that, an analysis, an opinion piece, not 'facts'. The only new 'fact' he bought into the discussion was one which was misrepresented, namely as the supposed abduction of innocent civilians. Either he did not know at this time that this 'fact' was very much disputed, or he deliberately 'forgot'. His claim actually seems quite unlikely considering the relationship between the abductees and their father, a Hamas commander. If these are the 'facts' Chomsky is going to add to the discussion, he quite honestly seems little better than the media he is accusing.
It's all simply a matter of looking at a very very very long chain of events and make a decision on where in that chain to lay the blame for the current conflict. He notes that Gaza is constantly under attack. Sure, but Gaza has also constantly been used as initially a staging ground for suicide bombers and now for rocket attacks. This blame game is interesting from a political and historical perspective and certainly very effective as a motivator to keep fighting, but obviously it will not bring peace any closer. For that we need de-escalation not demonization.