Because they had evidence that made the wet market theory the one most likely to be true, and a lack of stronger evidence for the lab leak theory. Investigating and supporting the theory that is best supported by the evidence you have isn't crazy, it's science.
When you look at all the facts you have, and then ignore that because it doesn't support what you want to be true, and then you act on what you wish was true instead, that's crazy. That's exactly what Trump and many of his supporters were doing.
We have new evidence now that suggests the lab leak theory is more likely than the wet market one, so once it is released non-crazy people will support the lab leak theory when they could not (and should not) have before.
sorry but what was evidence supporting wet market theory when this article was published
https://www.nytimes.com/2020/02/19/health/coronavirus-animal...
> The new virus seems to have leapt from wildlife to humans in a seafood and meat market in Wuhan, China, where live animals were slaughtered and sold as food.
https://www.nytimes.com/2020/02/10/science/pangolin-coronavi...
None of these qualify as evidence that you say the claim was based on.
There was a lot of evidence supporting the wet market theory at the time and supporting that it wasn't made in a lab (https://www.nature.com/articles/s41591-020-0820-9) including exposure to the market by early patients (https://www.thelancet.com/journals/lancet/article/PIIS0140-6...) and the fact that wet markets have been guilty of spreading similar diseases in the past (https://pubmed.ncbi.nlm.nih.gov/14738798/)
You do realise that when people say it was a lab leak, they don't necessarily mean it was made in a lab. They are merely saying that the origin of the pandemic was a virus escaping the nearby Wuhan Institute of Virology via one of the workers/researchers there.
The idea that someone in the lab down the street was accidentally infected with something from the lab and then went to lunch is far more plausible than creatures from thousands of miles away introduced a disease down the street street from a lab working on viruses that are known to be almost identical to the one of interest.
There’s no issue with pursuing all leads, but obviously some are much more plausible than others.
We know that because…?
"Raccoon dogs, marmots, civets, mink, Siberian badgers and many other furry mammals that could have served as intermediate hosts for the SARS-CoV-2 virus were openly, illegally and profitably sold in the market. The wild and farmed animals were documented to be in poor health, and crowded together in their cages."
https://www.tandfonline.com/doi/full/10.1080/00396338.2021.2...
"Live animals that are susceptible to COVID-19 were in the market in December 2019"
https://www.npr.org/sections/goatsandsoda/2023/02/28/1160162...
pangolin werent sold at wet markets though ?