The Venice Biennale is meant to challenge and disrupt. The eighteenth international architecture exhibition, curated by the Ghanaian-Scottish academic, educator and novelist Lesley Lokko, focuses on Africa and is dedicated to the ‘laboratory of the future’. But three exhibits on China offer an unplanned insight into contending visions of that future.

Approaching the venerable Arsenal of the Venetian Republic down a sun-baked alley, the visitor notices a small gateway adorned by Chinese characters. Stepping inside a courtyard, they enter a multi-media environment dedicated to ‘Transformative Hong Kong’.

This fringe exhibit is sponsored by institutions in Hong Kong with support from a Chinese corporation. Displays of drawings, photographs and text show ambitious plans to ‘green’ the metropolis while integrating it with the conurbations and industries of the Pearl River Delta. This is known as the ‘Greater Bay Area’.

Faultless in execution, fastidious in style, the works are a tribute to the skills of Hong Kong’s urban planners and architects. They speak of adapting the city to the fourth industrial revolution, adapting densely populated urban districts to low-carbon lifestyles and creating infrastructure to knit together a prosperous zone of south China.

There is just one thing missing – the politics of architecture. Since this is a theme pursued (relentlessly, some might think) throughout the Biennale, its absence is strange. It may be an oversight. Perhaps there was no space to mention that competing visions of Hong Kong’s future lie at the core of its upheavals and have led to the suppression of democracy, the imprisonment of activists and the imposition of a National Security Law that brings the city under the vague but absolutist powers which reign over the rest of China. Or maybe that was all too difficult.

Blandness, one soon understands, is a cultural weapon. That is clear on moving to the second room of the Hong Kong exhibit, which by something of a stretch links local urban renewal to the generosity and warmth of Chinese investment in Africa (presumably in deference to Ms Lokko’s chosen theme). A multi-screen digital video presentation, reflected in shiny floor panels, replays scenes of happy Chinese and African workers toiling on building sites without much in the way of safety gear. The pictures alternate with meaningless feel-good slogans about our shared future. It’s possible some might be influenced by messaging of this kind. Since I was the only one there it was not possible to say.

One emerges into the sunlight and crosses the alley into a gigantic elongated hall which once housed the Serene Republic’s shipbuilding and dockyard works. People walk through vast spaces to reach the People’s Republic of China’s exhibit. It involves fifty huge red scrolls adapted to house displays of architectural drawings, records and plans. The theme is ‘Renewal.’ Professor Ruan Xing, the head of the Chinese team, proudly explains that it testifies to the role of architects in the remarkable economic progress and ‘urban transformation of the world’s most populous country’. It is hard to disagree.

Comforted by the thought that all is well in the world’s most populous country, the visitor moves on, only to come up short on encountering a giant black cube. Ominously for cultural bureaucrats of all stripes, this exhibit is not affiliated to a state. It is the work of a co-operative based in the Netherlands and its title signals neither virtue nor blandness.

‘Killing Architects’ examines the infrastructure of Chinese policy in Xinjiang, a vast region of western China where the regime of President Xi Jinping has employed technology and surveillance to place the Muslim inhabitants under the strictest population controls to be found anywhere outside North Korea.

It consists of three elements. Inside the cube a small cinema replays a documentary film by the British architect-journalist Alison Killing and her team using satellite imagery and digital enhancement to show how buildings, including schools, have been turned into detention camps for the mass incarceration of local people.

On an external wall, portraits by the photographer Ekaterina Anchevskaya illustrate men and women who testify to abuses and grim conditions (all of which are denied by the Chinese authorities).

The third, most striking, element takes up the entire rear wall of the cube. It is a giant ink drawing of the Mongolküre detention camp by illustrator Jan Rothuizen. Done in cartoon style, it shows dormitories, workshops, guard quarters, walls, watchtowers and a sinister-looking infirmary. The captions say that some prisoners are given injections of unknown medication against their will and that the sterilisation rate in the camps is 243 per 100,000 people versus 32 per 100,000 in the general population. The word ‘genocide’ is prominent.

The effect is not unlike Picasso’s Guernica in the Reina Sofia Museum in Madrid. Both works of art are graphic and contentious. (Picasso’s is meant to horrify, Rothuizen’s is subtler and somehow more effective for it). Both deal with atrocities whose truth is argued over. Very well, they are there for viewers to judge.

It will come as no surprise that the Chinese embassy in Italy took exception to this. Its diplomats have form in trying to suppress anything they do not like in their host country. Somewhere in the foreign ministry in Beijing there must be a department that trains them in outbursts of confected indignation on subjects from sovereignty to music. In due course, some functionary discovered the Xinjiang exhibit.

Thanks to reporting by the estimable Venetian daily Il Gazzettino we know that the usual ‘stern representations’ were made. When these were rebuffed, the embassy cancelled an appearance by ambassador Jia Guide at the inauguration of the Chinese exhibit, leaving Professor Ruan to handle a lower-key launch. Some forty invitees to a gala dinner at one of Venice’s fanciest hotels got emails saying it was off due to ‘unforeseen circumstances’. The embassy issued a statement complaining about ‘fake news’ at the Biennale and ‘lies’ about China.

Here’s the point. After huffing and puffing, China did precisely nothing. Its room of giant scrolls remains open. So does the deserted Hong Kong exhibit. Visitors to the Biennale may therefore see, hear and decide for themselves which impression of the Asian colossus to take away. That is what Ms Lokko and the Biennale have achieved – and all credit to them. Let timorous curators and academics in the rest of the ‘free world’ take note.