How the media covers its tracks when proven wrong
twitter.com
twitter.com
A year of evidence gathering produced some data to support one of the claims. That claim is no longer tagged as fringe.
OP's link is to a twit'r who examines this case - where media rejects claim when it is baseless and and later accepts it when it gains material support. Twitr's conclusion is this proves media bias.
A year of evidence gathering by the "conspiracy theorists" found more and more credible evidence, and it reached the point the media could no longer cover it up. Now the media acts like they never labeled it a "fringe conspiracy theory" in the first place.
When there is no evidence to support a claim and the science indicates that it unlikely to be true, I expect headlines to reflect that. Similarly, if we later gather evidence that changes what we believe to be most probably true, I expect headlines follow suit. And that looks to be exactly what happened.
The only bias I see here are the broken clocks thinking they contributed anything of value.
Also, how exactly did "science" indicate it as being unlikely true? Coming from a person who likely believed it came from someone eating a bat sandwich...bc CNN told them to believe that.
Because you asked, the expert consensus at the time was that it was highly improbable that the virus was of lab origin:
https://www.nature.com/articles/s41591-020-0820-9
While you're right that laypeople in media and on twitter indulge in absolutes and sensationalism, the science seemed to be carried out appropriately. So if knocking over straw men is your thing, twitter is the more appropriate venue.