In any war, onlookers from far outside the conflict zone have to decide what to believe about what is happening. This sounds difficult in theory, and it’s even more so in practice. This week, after a deadly explosion at the al-Ahli Hospital in Gaza City, anybody checking social media for news would have immediately seen conflicting stories about what had happened. Initial news reports cited Gaza’s health ministry in asserting that the blast had come from an Israeli air strike. Almost instantly, counter-stories blaming the Palestinians went viral. On Wednesday, President Joe Biden said that data from the U.S. Defense Department had convinced him that the blast was caused by a malfunctioning Islamic Jihad rocket, and some open-source intelligence researchers cautiously agreed with that version of events. More detailed analyses are still pending, but a broader meaning of the hospital story has already been well established: It is “misformation” one way or another, circulated cynically to slander Israel or Palestine, depending on your worldview. Some facts about the war are, of course, clear. In Hamas’s …