If the Chinese guy is based in China, and he is paying with his hard earned Renminbi yes, you are subject to Chinese law.

Nevertheless Chinese government can start seizing your assets in China and transfers from or to you where other participant is in China.

And arrest you in case of visiting place within Chinese jurisdiction.

Unfun fact: there were multiple cases of people getting arrested after plane performed unexpected emergency landing in a country where landing was not planned. Both where arrest was justified and where it was not.

If you set up a company that accepts money from Chinese citizens and let them do stuff online I am pretty sure your company will be subject to Chinese law, yes.

If you are a business, that does business in some other country, you also have to comply to their local laws. Even if you don't have a presence there.

As a one-off donation? Probably not.

As a business? For sure. Not for every aspect of Chinese law, but for relevant ones and with enforcement in China or through mutual agreements with other governments.

This kind of comment is disappointing.

It shows a major lack of understanding of how law and businesses work, coated in a huge layer of outrage, all wrapped up in a Twitter-length type comment.