So it's the Israelis fault Hamas builds terror tunnels instead of bomb shelters??
That's a very transparent attempt to shift the goalposts.
Years ago, on the great-grandparent DB of this current DB, a number of posters were complaining about the PA not taking out terrorists fast enough to suit Israel. So I asked them if they supported giving the PA the weapons, equipment, and training it needed to take on a modern terrorist force like Hamas. All of a sudden, those same posters were screaming about what a terrible idea it was for the PA to be able to mount an FBI-quality surveillance program, or to have the equivalent of Delta Force fighters trained and equipped to take down the worst of the worst. They wanted to make the PA responsible for fighting terrorism but they didn't want the PA to be strong enough to actually do it.
I believe a similar thought process is behind the complaints about Hamas not building bomb shelters. I think some posters want to blame Hamas for the lack of shelters Gazans can use when Israel sends artillery fire, missiles, and drones their way, but at the same time they don't want there to be bomb shelters where Hamas fighters and their supporters can be safe from artillery fire, missiles, and drones.
So that's why I am asking you if you honestly think Israel will let Hamas build bomb shelters. If the answer is yes, I think you have a very unrealistic view of things. If the answer is no, then why blame Hamas for not doing something they couldn't do anyway?