Thanks for the ping. Great article by Glick.
The minute we relativize terror - the minute, that is, that we declare that it is defensible in some circumstances - we make it defensible everywhere. You say it's a legitimate form of warfare in Tel Aviv but not in London? I say it's legitimate in London but not in Paris (the French have no soldiers in Iraq), and someone else will say it's legitimate in Paris but not in Prague (there's no large, lower-class, discriminated-against Muslim minority in the Czech Republic).
The ideologists of terror seek to justify themselves by claiming that the murders they commit are not indiscriminate, since they distinguish between innocent and guilty countries. This is true. What terrorists do not do is distinguish between innocent and guilty people. From their point of view, no one living in a country that is guilty - Israel, for example - can be innocent.
To accept this contention, or even to condone it in part, is to undermine the entire basis of Western morality. It is to revert to the law of tribal warfare and the blood feud, the idea that, if someone from your tribe kills someone from my tribe, your life is forfeit.