That's because Kent State massacre is not a politically incorrect topic in the West. What happens when you ask ChatGPT about a genuinely politically incorrect topic in the West?
So at best the complaint boils down to this: China has the wrong politically incorrect topics and we have the right politically incorrect topics. And of course, once the complaint is reduced to this form, its irrelevance to the topic at hand (LLMs) is evident.
GPT won't let you be a bigot, this model won't discuss the historical fact that thousands of people were murdered by the Chinese state. That's a complete false equivalence.
in the West, "politically incorrect" means that a topic is liable to offend people. examples include HIV rates (LGBT people), racial crime statistics (racial minorities), shari'a (Muslims), etc. in contrast, Tiananmen square is just embarrassing for the CCP. so it seems like you're making a false equivalence.