> If you think that the US is doing this for the protesters

Is that really relevant?

I mean, HKers are getting screwed by a massively totalitarian and oppressive regime. Why is the interest of a third party relevant to the Chinese regime's devastation of Hong Kong?

... international agreements protecting democracy and freedom of expression in Hong Kong. The US isn’t doing this for protestors, and it will be terrible for HK, but it ultimately is because of China’s attack on HK freedoms

A thing can be for more than one reason at once.

Of course the US wouldn't have done this had it been against the US' interests.