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...
And in there, I describe exactly how wrong your point 1 is. And how misguided your point 3 is.
The post also won a "best of r/science 2020" award!
You can find it here: https://www.reddit.com/r/science/comments/gk6y95/covid19_did...
Because those mutation events in a small number of people still require a longer time to become "stable" in the overall population of viruses.
Generally speaking, the more virus "generations" you have, the more likely you are to generate a successful variant. But then it takes time for that variant to achieve dynamic equilibrium in the greater population of viruses. For it to take over.
And the initial SARS-CoV-2 had so little diversity for so long, that we can say it likely had been stable before passing into humans, or there would have been more initial diversity in it compared to its closest viral relatives.
It is a picture overall consistent with a random crossover event. Not ruling out a lab leak (because that's quite difficult if not impossible to do). The absence of evidence is not evidence of absence.
But we have just as much evidence to say the virus came from aliens who planted it in humans as we do to say it came from a human lab that has no trace of the virus anywhere in it.