You're missing his point.
And thank you very much for making my point.
Why, indeed.
We should support Israel because they’re generally in the right regarding their right to exist. They’re under attack not because they displaced indigenous tribes of Arabs who want justice, but because they represent an idea ("Western culture" including freedom and democracy) that threatens their Islamo-fascist neighbors. And we have a moral responsibility (for our own benefit) to defend good from evil everywhere, depending on our ability.
The defeat of Israel would empower radical Islam around the world, and allow their version of history to prevail, the one that labels Israel and the West as aggressors. I’m not well informed on Islam, but I’ve read enough here to presume that Moslems are not going to be satisfied with integrating into the West and adjusting into a compatible role.
I think that either Western or Islamic values clash for dominance everywhere they coexist. Israel is as much a thrust into the heartland of Islam with Western values as the closest mosque is to your values. (And I say this as an atheist.)
I know the above wonders a little, but I needed to make a point first: Israel is a representative of our values in a frequently violent clash of values. If you accept just that, then please let me rephrase your question: “Why should we support our western values?”