Some might well turn China’s conspiracy theory around and accuse the host country of attempting to infect a new virus into military personnel of 110 countries around the world, right before they returned to their home countries. In addition to military personnel from the United States, the games in Wuhan hosted military personnel from almost all of the NATO countries, South Korea, bordering countries like Russia, India, Pakistan, Nepal, Myanmar, Vietnam, and quite a few countries in Africa, where the local health-care systems would be terribly unprepared for a threat on the scale of SARS-CoV-2. If SARS-CoV-2 had quietly spread among the military personnel at the games in Wuhan before they returned, the host country could have set off a health crisis in the ranks of military forces all around the world.
As I see it, the known facts just don’t fit this theory. For starters, as far as we know, no athletes who participated in the games in Wuhan have been diagnosed with coronavirus — and that’s not the sort of information that could be easily suppressed simultaneously by lots of militaries around the world. The timeline doesn’t fit, even with lengthy incubation period. And even if the Chinese military did want to set off some sort of terrible bioweapons attack on the militaries of the world, there would be no way to ensure they didn’t get exactly the kind of disaster that befell their own country and civilians. If a malevolent government was going to do something like this, it would make much more sense to do it at a global military event even they weren’t hosting — and particularly not when they were hosting the military games in a city with two separate laboratories researching coronaviruses in bats.
All they had to do is read Tom Clancy's book Rainbow Six to get this idea. If you have not read the book, elite environmentalists come up with the idea to release an Ebola strain at the closing ceremony of the Olympic games to infect people around the world and kill off 99% of the population.