Maybe their position is that they have not established as a fact that there is slave labour in concentration camps in Xinjiang? Have you considered that as an alternative possibility?
From the article:
> The letter now reads that the company prohibits "any human trafficked or involuntary labour such as forced, debt bonded, prison, indentured, or slave labour throughout your extended supply chains."
That automatically covers Xinjiang is there is slave labour there, in additional to all other instances of slave labour, no? That sounds like a better wording than the original.