Yes, the "Security Fence" is bad.
Here’s why: It will alienate Jews from their identity.
The primary reason for the existence of the Zionist movement was the reconstitution of the Jewish state. The most vital ingredient in that mission was the revival of Jewish attachment to the Jewish Land on the Land.
However, every generation since the re-establishment of the state has been dwindling ideologically, due to years of leadership without purpose.
The greatest evidence of this weakening is the general acceptance of the myth "Arab" rights to parts of the Jewish Homeland by Israeli's--the greatest dupe of all times.
In light of the weakening of the Jews, there can be little doubt that future generations of the Jewish people will see the fence as the rightful border of the State of Palestine. Thus, the fence will create the impression that Jews should not live beyond its position; alienating Jews from their crucial Birthright.
Eventually, the fence itself it will be viewed as cruel barrier between Israel and peaceful “Palestinians”. More, it will be called barrier to normalized relations between both states west of the Jordan River and, thus, a barrier to peace itself.
Finally, the myth a “Palestinian nation” will be formalized within the minds of our future generations, which will undermine the Jewish Birthright. This will result in a diminished concept of Jewish identity for Jews everywhere.
That’s enough to make it a bad thing.