[tropo]

Lots of reasons:

There is a difference between "seems obviously correct" and "proven well enough to avoid a lawsuit".

China exerts control over American media companies. Ones that don't play ball get banned in China. Remember that these companies are usually involved in many businesses, including the sale of movies to China's large population. Everybody is afraid to upset China.

Even the publisher of Nature has ditched about 1000 articles that were upsetting to the Chinese government.

Much of the US media is strongly in opposition to the US president. (They even stopped airing his virus updates, despite good ratings, because it was making him look good.) There is no desire to spread any news that could support his opposition to China.