Maybe the virus was not a pandemic 20k years ago. Small tribes that carried genes that are resistant to the coronaviruses spread later on as they established larger communities/cities.
"Dr. Goldstein noted that the testing paper listed the individual mutations the Wuhan researchers found in their tests. Although the full sequences are no longer in the archive, the key information has been public for over a year, he said."
The CDC’s Dr. Thornburg and Josh Denny, chief executive of the NIH’s All of Us program and an author of the latest study, both said they don’t plan to search blood samples earlier than December 2019, given how few they have found back then. “We’ve seen a very low rate of positivity in this time period,” [1]
Except the evidence that the virus came from a lab leak is provided by the American government, the arguments are constructed by Americans, and the news leaked and propagated by the American press and American social media networks.
The other side of the debate use the same American tools.
This is more a civil war in American discourse between the liberals and conservatives than anything else.