The answer is that it makes Israel safer. Cast lead restored Israel detterence and we had a number of years of relative quiet, that's pretty nice if you happen to live in one of the towns near the border with Gaza. Iron dome also makes Israel safer, I suspect that's why it's pissing off so many of the Israel haters.
High school teacher's union threatens strike (Haaretz)
from the article: Iron Dome makes world history intercepting nine Gaza rockets