I'm not from China, from my perspective, those companies are from around the world.
I'm curious too - was there really no non-Chinese company that would endorse this?
W3C members are visible here: https://www.w3.org/Consortium/Member/List
Those are the members that decided that WebAssembly is now an official web standard, not the testimonials.
I'm investigating more about the voting system here, https://www.w3.org/Consortium/Process/ERB.html.