I have some questions about this person's argument which I'm posting here in hopes that someone with more expertise can answer them for me.

The crux of his argument seems to be that serial passaging could not have produced the virus because a petri dish is unable to adequately model human tissue.

The takeaway is that the SARS-CoV-2 virus mutates in predictable ways when you remove it from a body and put it into a petri dish. These changes include genetic deletions that make the coronavirus less likely to infect humans.

SARS-CoV-2 is so highly adapted to being inside living mammals, that once you move it into a petri dish, it leaves a trail of evidence.

I was wondering if this also holds true for more sophisticated in vitro tissue models like the one described here?

The scientists also tried their infectious SARS clones in something called an air-liquid interface, using a relatively new type of cell culture developed by Raymond Pickles of the University of North Carolina’s Cystic Fibrosis Center. Pickles had perfected a method of emulating the traits of human airway tissue by cultivating cells taken from lung-disease patients — nurturing the culture over four to six weeks in such a way that the cells differentiated and developed a crop of tiny moving hairs, or cilia, on top and goblet cells within that produced real human mucus. In fact, before infecting these HAE (human airway epithelial) cells with a virus, the lab worker must sometimes rinse off some of the accumulated mucus, as if helping the lab-grown tissue to clear its throat. So Baric was exposing and adapting his engineered viruses to an extraordinarily true-to-life environment — the juicy, sticky, hairy inner surface of our breathing apparatus.

Also, is there not the possibility of passing the virus through actual in vivo models like primates? Biologists like Frank Olsen used to kill monkeys by the dozens at Ft. Detrick during the development of the bioweapons that were used by the CIA in the Korean War.

I'm extremely skeptical of the Wuhan lab-leak narrative. The reason I'm still curious about any the possibility of any lab preparation is because I'm convinced that the US has been waging hybrid biowarfare on Chinese agriculture, and I don't believe that they're above attacking humans either.