A stone pulpit in the National Cathedral in Washington, D.C., is no place the chef José Andrés expected to be when he created the food charity World Central Kitchen nearly 15 years ago. But on Thursday he stood there, eulogizing seven of the organization’s workers who were killed in the Gaza Strip while trying to carry out a singular mission: bringing food into a region of 2.2 million people facing a growing humanitarian crisis. “They risked everything to feed people they did not know and will never meet,” Mr. Andrés said. “They were the best of humanity.” The seven workers were killed on April 1 after they helped unload a barge of food aid in northern Gaza and were heading to the southern city Rafah.

Their well-marked convoy of vehicles was hit by armed Israeli drones. Israeli military officials said the attack was a serious mistake that shouldn’t have happened. They cited a series of failures, including a breakdown in communication and violations of the military’s own rules of engagement. An unusually subdued and occasionally tearful Mr. Andrés said he was consumed with regret, sorrow and anger over the deaths. “I know there are also many questions about why World Central Kitchen was in Gaza,” he said. “We ask ourselves the same questions day and night.”