Adam Louis-Klein, a Jewish anthropologist, was living in an indigenous village in Colombia’s Amazon rainforest on October 7, 2023, studying the local Desana people, with no phone service or internet access. Two days later, he made his way to a nearby town and reconnected to the wider world for the first time in months. The first thing he saw was news of the Hamas slaughter in Israel. The second was his leftist colleagues justifying the terrorist invasion. He posted “Am Yisrael Chai” on Facebook and was berated for it. “I was already starting to be purged. I soon lost virtually...