You raise good points, but note that not everyone is rational here. Covid has in fact shown irrational so many people are, even in the 21st century.
If it were discovered to be a lab leak from something previously discovered in the wild, especially from a NIH funded lab, hell would break lose and it would hurt many aspects of biological and medical research.
If authorities decide based on political considerations to not investigate a mistake that led to millions of deaths and tens of millions more lives destroyed, they lose an enormous amount of credibility in the eyes of the public.
Full integrity is the only chance we have of having a healthy political atmosphere where the public can trust the establishment.
If it were discovered to be a lab leak from something previously discovered in the wild, especially from a NIH funded lab, hell would break lose and it would hurt many aspects of biological and medical research.