Earlier quoted context omitted.
It's estimated that Hamas has between 30,000 and 40,000 soldiers(1), which is about 6% to 8% of Gaza's entire adult male population. There's no way of getting around it: if Israel finishes the job of eradicating Hamas, a large percentage of the Gazan population will be killed or captured, purely because so many of them are actively involved in Hamas. Anyway, if Gazan citizens learn the lessons of their mistakes, they…
Then that means we're looking at ~150,000 to 200,000 Israeli casualties. Roughly a fourth of all their trained personnel and a seventh of all the males available for conscription. Nearly all of Gaza is built up urban centers and Hamas has had a decade plus of preparation time for this event. The urban fighting for the attackers is going to be some of the worst since Leningrad. It's going to take years to fully clean…
There is zero reason to think the IDF is going to take that many casualties. They are much better equipped than Hamas, and if needed, they can simply besiege areas to force Hamas to either leave or starve.