As Covid-19 tore through the United States in 2020, Elon Musk, Tesla Inc’s billionaire owner, described lockdowns in the country as “fascist” and a violation of citizens’ freedoms. Two years later, amid far more stringent restrictions in Shanghai, Musk has levelled no such criticism of Beijing’s pandemic response. The contrast reflected what some human rights advocates and US lawmakers consider a too-friendly relationship between the world’s richest man and authorities in China, Tesla’s second-largest market and a key manufacturing hub for the electric automobile maker. And so, when Twitter accepted Musk’s offer to buy the popular microblogging platform last month,...