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 was a lot of controversy around the P4 lab in Wuhan when it was built, as this was seen an unnecessary risk. There has been breaches of security protocols several times in the past.
The fact that a new virus would first appear in that city would have been quite a coincidence that could not be ruled out, but the accidental lab release should always have been an hypothesis.