BEIJING—At least one Chinese online retailer appeared to drop H&M’s products amid social media attacks on the Swedish company for saying it was “deeply concerned” about reports of forced labor in the far-western region of Xinjiang. The European Union, United States, Britain, and Canada on Monday imposed sanctions on Chinese officials accusing them of human rights abuses in Xinjiang. China retaliated with sanctions on European lawmakers and institutions. H&M had previously said in a statement it was “deeply concerned by reports from civil society organizations and media that include accusations of forced labor” and that it did not source products from Xinjiang. Activists and some Western politicians accuse China of using torture, forced labor, and sterilization of Uyghur Muslims in Xinjiang. It was not immediately clear why an old statement from H&M, which media had reported last year, about the cotton-producing region was back in the public eye. H&M’s official …