Because the hostages aren’t why we need the ceasefire. We need it to deliver aid. Also it’s an Israeli pre-condition. So what the white house is doing is putting the one big thing Israel wants and telling Hamas they’ll get a temporary peace out of it. Hamas has no reason to take that deal. Israel would similarly tell the white house to pound sand if they showed up in Tel Aviv to say Hamas has a deal that just requires the removal of all IDF troops from Palestinian territory.