It absolutely had everything to do with Trump. He was slated to be the clear winner until two events (COVID-19 and George Floyd) presented political opportunities. In an election year, everything becomes about the election. People wanted to attack Trump at every turn, even when he suggested reasonable measures like controlling travel, and equally they wanted to ensure all blame was directed at Trump rather than the Chinese government or state governments or elsewhere.
To address your claim more directly, there was never any justification to dismiss the lab leak theory, or claim it was debunked (as many news outlets did), or censor conversations about it online. This isn't about believing it is the only possibility, but that it is a likely possibility that deserves serious attention. The reason it was instead cloaked in dogmatic terms like "conspiracy theory" and shutdown outright, is purely because of politics. There was no "real evidence" to dismiss it as it was. And guess what - that dismissal also allowed the Chinese government to avoid a site visit for months, and even when the WHO visit happened, it was under the terms of the Chinese government with an untrustworthy outcome. Those who shutdown the lab leak theory and other such claims aren't interested in evidence. They're interested in political opportunism.
> there is zero evidence of a lab leak besides circumstantial.
First, there are credible, credentialed virologists saying that the lab leak hypothesis has not been ruled out, and that it has been inadequately investigated [1].
Second, there are real anomalies in the Covid genome [2] that seem unlikely to have occurred naturally:
however, several characteristics of SARS-CoV-2 taken together are not easily explained by a natural zoonotic origin hypothesis. These include a low rate of evolution in the early phase of transmission; the lack of evidence for recombination events; a high pre-existing binding to human angiotensin-converting enzyme 2 (ACE2); a novel furin cleavage site (FCS) insert; a flat ganglioside-binding domain (GBD) of the spike protein which conflicts with host evasion survival patterns exhibited by other coronaviruses; and high human and mouse peptide mimicry.
In particular, the furin cleavage site is extremely interesting because it's exactly the type of genetic manipulation done in gain of function research that was ongoing at the Wuhan Institute of Virology. More on the FCS:
Because the presence and coding sequence of a FCS is important for pathogenesis, host range, and cell tropism (Nagai et al. 1993; Millet et al. 2015), the addition of a FCS into viruses has been an active area of gain-of-function research. A FCS can be easily inserted using seamless technology (Yount et al. 2002; Sirotkin and Sirotkin 2020) without any need for cell passage, as previously performed in experiments on virulence and host tropism (Cheng et al. 2019). Insertions to change the properties of SARS-r CoV viruses are documented by Ren et al. (2008) and Wang et al. (2008). Considering that natural mutations have a very low probability to result in a stretch of 12 amino acids coding for an optimized FCS without any known intermediate form in Sarbecovirus, an artificial insertion of the FCS in SARS-CoV-2 may provide a more parsimonious explanation for its presence than natural evolution.
In summary, the FCS confers SARS-CoV-2 enhanced human pathogenicity and has never been identified in another Sarbecovirus. At the same time, FCSs have been routinely inserted into coronaviruses in gain-of-function experiments, and we provide a hypothesis through which the specific amino acid sequence of SARS-CoV-2′s FCS may have been generated through cell culture.
> extraordinary claims require extraordinary evidence. there is zero evidence of a lab leak besides circumstantial.
The claim is not exactly extraordinary - you have a lab with a history of poor controls, performing gain of function research relating to SARS-like viruses, knowing that SARS (the first one) had broken out of labs multiple times. That's not hard evidence, but it is a strong set of priors that makes the lab leak theory an obvious candidate for an origin story. It shouldn't be surprising that there isn't hard evidence when the world hasn't been allowed a timely and transparent investigation. And why would China allow such an investigation when there's no pressure to do so, when people are rushing to their defense to dismiss the valid lab leak theory as a "conspiracy theory"? Their work was done for them by news media and tech giants who institutionalized that dismissive attitude, again motivated by their own political biases. You can't have evidence until you take the speculation seriously and perform the necessary investigation properly, so I'm not sure how you could for "extraordinary evidence".
> weird how that works, huh?
You're ignoring the point I was making, which was that the people opposed to Trump were desperate for any way to attack him, given that he was on a clear path to re-election. Since this was the only crisis at the time that they could leverage, they did so (and did so viciously). That included dismissing any scrutiny directed at China, even though it was valid.