That reason?
Hate Crimes - https://www.npr.org/2021/08/12/1027236499/anti-asian-hate-cr...
Even in my small town of 7000, an Indian lady was assaulted to "get back at those Chinese for giving us COVID (which doesn't exist and is just made up by the lame stream media)".
Anti-Asian hate crimes are a real thing, but both black and white Americans endure them at a higher rate[1]. Further, these types of attacks went up across the board during the pandemic however Asian based hate crimes represented only ~8% of these attacks with most other ethnic groups having way more attacks targeted at them[2]. Seems to me like an example of cherry picked statistics being used for political gain. Asian hate crimes being something that became way more common during the pandemic is simply not grounded in reality.
https://www.statista.com/statistics/737681/number-of-racial-...
https://www.justice.gov/crs/highlights/2021-hate-crime-stati...
It must have been really obvious to all concerned that, by running to ground the lab leak theory, if it ever did get out (what they did) that it’d be a big net loss for trust in government and science.
So it follows that they must have been really (like really /really/) scared that it was absolutely necessary — damn the consequences.
But my guess it’s actually a feedback loop gone out of control. (We knew even then that this was no Ebola.)
At the same time, in the UK, right at the start, we have those now famous words: people were “made to feel more personally vulnerable”.
My guess is that the intended recipient of that initiative was us (i.e., gen pop), but the acute recipients (i.e., those most likely to hear, actively listen and be influenced) were those already involved in the campaign.
The volume could not be turned down (because it was assumed gen pop would otherwise not listen). But very stupidly, there also was no moderating mechanism for those “in charge”. So we have our loop.
(This doesn’t fully track, because later the British PM got seriously ill. And later still, the British PM also went back to partying. So, there would have been re-injected some non-trivial rationale to the severity worries, albeit only later. And there was also apparently a very effective moderating mechanism at least in central government. But as a simple model, it explains a lot for me.)
But a lab leak in itself would be a big loss of public trust in science. It exemplifies the worst fears of the uneducated regarding "God-playing scientists" who slice and dice the DNA like a Frankenstein, produce plagues for curiosity and "we were preoccupied with whether we could, but not whether we should"-style tropes. A real leak would validate these nutteries and play into the cards of the woo anti-science people (remember those times? Penn and Teller's Bullshit etc...). The fear around GMO etc. And this sort of research is international and wasn't localized to China and the Wuhan experiments aren't solely with Chinese involvement. So they thought better roll the dice and see if it gets out.
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Trust is a very feeble thing, and nobody wants to do an honest postmortem. The train is simply moving forward faster and faster. Erode public trust, then smear and name-call anyone who doesn't adhere to an ever narrowing band of acceptable beliefs, dismiss them all as everything-ist nutjobs. Never admit wrong, just crank the heat up steadily year by year. Because surely that will solve the problems.
The alternative is to say that reality is A, have a lot of people face (just or unjust) repercussions, then say "Oopsie! Turns out we were dead wrong". The damage is already done by that point.