I don't hear any supporters of Palestinians shouting "Release the Hostages!"

Then you're not looking. Over 200 arrested at Grand Central Terminal during rally for ceasefire in Gaza
Splitting hairs, but here, at a protest for a cease fire, a passenger was quoted that they needed to go farther:

One passenger said he was not only angry because of delays but also, he says, because the demonstrators aren't talking about what caused the war - the terrorist group Hamas killing 1,400 Israelis and taking others hostage.

"Pre-mediated massacres. God bless you, my son. Hope you see the light," the passenger told a demonstrator.

Part of the problem is that the Israelis aren't discussing the negotiations to release their own people who are hostages.
Israel will not agree to a cease-fire, Netanyahu says, as fighting continues in Gaza

It sounds like Netanyahu has written them off. Or is everyone being quiet to not jinx negotiations?

Israeli officials would not comment on the status of negotiations over a deal to free hostages.

In Israel, Netanyahu has faced considerable political pressure over his handling of the conflict, including his limited contact with the families of people killed or taken hostage. And he is seen by critics as attempting to deflect responsibility for the deadliest attack on civilians in Israel's 75-year history.