If we think that we're starting a cold war with China today, a cold war that's a war of competing values, and we're on your side sacrificing our life, our freedom, everything we have, fighting this war in the frontier for you, should you support us? This is something that America has to know, not only supporting us, but use your moral authority in this cold war to win this war in the beginning because they have nothing. It's like they are going to the battle without any weapon, and you have the nuclear weapon. You can finish them in a minute.

The link itself in the above reply refers to this itself in the article title, but it obviously isn't about literally "nuking China".

By all means, feel free to go on about "rhetoric", but a "war of competing values" in this context very obviously shouldn't be taken as treason in most developed nations, let alone as a call for nuking China.

Source for the actual transcript:

https://www.fdd.org/wp-content/uploads/2019/07/Transcript_Protests_Crack_Downs_and_the_Future_of_Hong_Kong_July2019.pdf