why are some cities less important than others?

There is an argument that is offered that is considered pro-settlement, but it disturbs me whenever I hear it.

When the debate swirled around the dismantlement of Gush Katif, a major argument was that they are the front line for the rest of us. If we get rid of them, the terror will be that much closer. If they fall, we will have to contend with terror in Beer Sheva Jerusalem, Tel Aviv, etc.

When talking about allowing other areas to build, or other areas to get rid of, the same argument is often presented, that they are the front lines and prevent the terror from getting closer, to the main cities.

Today a certain structure was approved for building in the Jewish area of the Arab village of Silwan. In the ensuing debate, the leftists want the plan canceled, even though the land was legally purchased, and all the regular reasons. The representatives of the Amuta of Ir David, Elad, when asked by the Haredi media for their response, said, "You have to understand. If we don't continue buying land there and building there, in Ir David, you will have to fight for your right to live in Mea Shearim."

In other words, again, we are the front line and if we fall, you are next.

Is that really a good argument? Why is Meah Shearim more important then Ir David, that the reason to continue building in Ir David is to protect Meah Shearim? Why is Gush Katif less important than Beer Sheva, Sderot and Ofakim, that the reason to keep Gush Katif was so Sderot does not get hit? Why is Chomesh and other places in the Shomron less important than Netanya that the reason to keep them is so Netanya does not get hit?

Don't they deserve to stand on their own merits, and not just as protection for cities further in the borders?

There is an aspect of truth to it, as their presence keeps the front line that much further out, but they are not there in order to keep my house safe in bet Shemesh. They are there because they believe in settling the land, especially parts that are abandoned by most others. And that is great. But why is that specific argument legitimate?

Maybe one of the "settlers" reading this could try to explain the argument...