I expect that Hamas kill and torture spies and collaborators.
The Israelis, however, torture and kill Palestinians on a regular basis in their jails. They also rape Palestinians (men and women) and film them being raped in order to blackmail them into becoming an informant. They need to spy for the Shin Bet otherwise their families will see the film.
That is how the Israeli intelligence about Gaza is so "good".
"‘Arrested, tortured and insulted’, say workers returned to Gaza by Israel"
Now I bet you are going to say, "yes, but they are not Israeli citizens". OK, so tell me, what are they exactly?