I'm not jewish, yet I can still see the significance of the eruv. It appears to dennote a neighborhood. There should be no reason why using a perambulator to ferry children for a nice walk around the neighborhood should be forbidden, yet it is still important that commerce be banned. Presumably, no one inside the eruv would enagage in commercial activities, so any package would be non-commercial in nature. Outside the eruv, however, many shops are open-- and carrying a package there could be use for commercial arctivities not in keeping with the Sabbath.

In the same way that a breakin could be seen as a reason to reconsecrate a sanctuary, disturbance of the poles, wires, etc. is seen as a reason to require reconstruction of the eruv-- verification that no nonjews have set up shop within the bonderies, etc...