By actually considering the idea based on the information available, rather than judging solely on the messenger. Things we've known for most of the past year now:
* The wet-market was likely not the origin of the outbreak. Earliest identified positive cases predate the market outbreak and have no connection with it.
* The lab in question was very near to the wet market where the largest outbreak occurred.
* The lab in question specifically researched coronaviruses in bats.
* The closest match to the SARS-COV-2 virus we've found in bats in nature are bats that live over a 1000 kilometers away from Wuhan. However, these bats are among those being researched at the virology lab there.
* The lab in question was the subject of concern among international inspectors years before the outbreak, who stated that they believed the lab didn't meet necessary safety and containment protocols, and didn't have the staff to do so.
* US intelligence agencies have been signalling that the Chinese government has been covering up the origins of the lab.
* The CCP themselves have demonstrated that they are actively working against the discovery of the origins of the disease. Soon after the wet-market outbreak, they closed the wet-market, prevented any international scientists and experts from examining it, and over their objections, purged all animals there and sanitized the entire place, making it impossible to determine what might have led to an outbreak at the market. They also cracked down internally on whistleblowers who said the situation in Wuhan early in the pandemic was much worse than being broadcasted. Finally, they have simultaneously insisted on the natural origin of the virus, while also pushing theories that it originated from non-Chinese sources, such as China, South Asian pangolin black market traders, and the US Army.
* The CCP prevented WHO investigators from actually entering the country to look for origins of the virus for nearly a year, didn't give them full access when they arrived, and the resulting report was declared largely useless by the international community immediately upon its release.
* All people claiming that the lab-leak theory had been "debunked" were actually referring to the theory that it was genetically engineered, which is not the same thing at all.
None of this proves a lab leak, but its strong enough circumstantial evidence that it is at least as plausible as any other origin. Virtually the only new information to have come out is that some of the workers in the lab got sick with Covid-like symptoms in November.
If you swapped China with the US and this lab with the CDC, people would have taken it far more seriously. Imagine a worldwide pandemic started down the street from the CDC in Atlanta, Georgia, AND no one could find the origin of the virus but the closest match was in an animal native to Northern Ohio, AND that animal also happened to be at the CDC for studying the type of virus in question, AND whistleblowers had mentioned concerns about procedures there previously, AND the US government did everything in their power to prevent people from investigating. People would have zeroed in on the theory from day 1.
There was always plenty of reason to see it as worthy of consideration, and for those who weren't judging solely based on "Does Trump think this is true or not", they did. The biggest reason it wasn't was solely due to the fact that our media/social media can't function outside the scope of our current political/cultural wars. Information is being judged less and less on its own merits, and more and more on who is providing it.