China’s international mantra is that human rights start with a socio-economically stable foundation--before democratization. In other words, people need to eat breakfast before they cast ballots.
China is also an advocate of sovereignty and emphasizes not interfering in other countries’ internal affairs. This comes from interference by Western powers in the past, particularly Great Britain during the opium wars, who told the Chinese Imperial Court to give up its protests about the drugs being smuggled into the Chinese Empire, despite the social ills it was causing to Chinese society.
It’s unrealistic to ask China to demand that North Korea end its political prison system or to accept North Korean escapees as political refugees. China itself has the largest number of political prisoners in the world. Lists such as this one indicate only some of the thousands of people in China held in political prisons.
Overall, China has human rights issues similar to North Korea. It does, however, allow people slightly more freedom of expression than North Korea does as long as the Communist Party is not subject to rhetoric that undermines it.
For example, people have the right in China to say that things aren’t perfect, and people can sometimes air their opinions about certain issues like economic problems that need to be resolved.