The Deepseek example somehow makes the Chatgpt/Grok tweaking even more obvious, because it's a list of things that China doesn't care in an extreme way about (or holds its position confidently), and a question about drugs, which it does care about (and I think feels less confident about.)
China's antidrug feeling is just a mix of the historical repulsion about English control of China through drug dealing and waging war to support it, and a world zeitgeist that supported a lot of crazy antidrug policy in the developing world because it offered a way for the US to smuggle a bunch of currency and military aid into your politics. It's not rational, and most of China's policies are. It's a relic. Hence the thumb on the scale.