1. Gain of function research primarily uses samples collected from nature, and seeks to stimulate their evolution in as natural a way as possible to learn how viruses evolve in nature. If such viruses were to escape the lab, they would appear "natural"
2. It's not xenophobic for people from the US to suggest the possibility of a lab leak, because the US was itself funding gain of function research on novel coronaviruses in the Wuhan BSL4 lab
3. Lab leaks happen more often than most people realize[1]
[1]https://www.vox.com/future-perfect/2019/3/20/18260669/deadly...
There is, from my understanding, reasonable evidence to conclude the virus was not engineered from the perspective of "we took genes from one virus and moved them to this virus," but there's no evidence disproving the idea that it was the result of gain of function research.
My personal feeling is that these statements are true:
* The virus is unlikely to have been engineered (in the way I described above) and leaked.
* There is circumstantial evidence the virus was the result of gain of function research and it leaked.
* There is circumstantial evidence the virus was a natural research sample and it leaked.
* There is circumstantial evidence the virus was introduced by an animal/person who traveled to the wet market.
Some of these are more likely than others, and an individual's own calibration for what is likely or unlikely will probably come into play more than evidence in the short term and possibly long term as well. I can say the vast majority of us are not qualified to answer the question either way though.
Likely, unlikely, it's not really possible to attach probabilities to events that already happened. Also history is told chronologically, when told anti-chronologically we tend to make causal connections where there are none.
I don't want to dismiss the lab theory completely but consider this:
These kinds of labs are all over the world, in China, in the Netherlands, in the US and so on. They are mostly being built in metropole regions because that's where large science clusters tend to be. Coincidentally city centers are traditionally built around markets. These tend to be the densest areas of cities. Densest areas are where infection clusters are most likely to build up and get noticed.
And now we find a case where all these 3 coincide. Really, that doesn't say much. Also there have been quite some hints about Covid19 cases before December 2019, outside of China even. [1] Statistics is a highly counter-intuitive discipline. If it wasn't maybe the virus would be already under control anyway.
[1] https://www.bloomberg.com/news/articles/2020-12-01/covid-inf...