There isn't "the lab leak theory", there's at least 3:
* the lab had a sample of the virus that accidentally got out.
* the lab had modified another virus, that accidentally got out.
* the lab purposefully released the virus as an attack.
I get suspicious when people talk about "the" lab leak theory, because I never know which one they mean. People I've heard from in real life have generally intended #3. This article is arguing for #2. When the epidemiologists quoted in the article were talking, which were they referring to? #1 or #2?
