This looks like it's coming from a separate "safety mechanism". Remains to be seen how much censorship is baked into the weights. The earlier Qwen models freely talk about Tiananmen square when not served from China.

E.g. Qwen3 235B A22B Instruct 2507 gives an extensive reply starting with:

"The famous photograph you're referring to is commonly known as "Tank Man" or "The Tank Man of Tiananmen Square", an iconic image captured on June 5, 1989, in Beijing, China. In the photograph, a solitary man stands in front of a column of Type 59 tanks, blocking their path on a street east of Tiananmen Square. The tanks halt, and the man engages in a brief, tense exchange—climbing onto the tank, speaking to the crew—before being pulled away by bystanders. ..."

And later in the response even discusses the censorship:

"... In China, the event and the photograph are heavily censored. Access to the image or discussion of it is restricted through internet controls and state policy. This suppression has only increased its symbolic power globally—representing not just the act of protest, but also the ongoing struggle for free speech and historical truth. ..."