Elon Musk can’t stop posting about the political fringe. In recent weeks, the world’s wealthiest person used X to post about immigrants to Britain, saying they will cause the country’s collapse. He posted about examples of violent crime in Minnesota and South Carolina — where he does not live — and about judges in California and New York he believes are too lenient. Musk also smeared trans people, complained about Black-on-white crime, stoked fear about the end of civilization and shared his thoughts about the race of child actors. Musk posted about all those topics and more in a recent...