I would have. English is a frankenstein language, adopting words from all sorts of different languages. Kowtow means what it means in English, it's a perfectly reasonable word to have used there.

I tried really hard to see if this wasn't the case, but the consensus across the web seems to align with this SO post: https://english.stackexchange.com/questions/314900/does-kowt...

IMO, he was being downvoted because this particular instance is just as much a show of kowtowing to the US government as the Chinese government.