I think that it is at least somewhat likely that it was the result of the lab's activities, but your assertion here has a huge dose of selection bias.
If the virology labs studying coronaviruses were placed randomly around the world, you'd be correct - but they're not. They're placed near locations where novel coronaviruses have crossed the species barrier in the past, and where they are likely to do so in the future.
It would be equivalent to say that lighthouses cause ships to run aground, because many teams when ships run aground it's near a lighthouse.
> We have done bat virus surveillance in Hubei Province for many years, but have not found that bats in Wuhan or even the wider Hubei Province carry any coronaviruses that are closely related to SARS-CoV-2. I don't think the spillover from bats to humans occurred in Wuhan or in Hubei Province.
https://www.sciencemag.org/sites/default/files/Shi%20Zhengli...
So I think it's entirely possible e.g. that China has confidently determined the non-lab origin of SARS-CoV-2, but that it's from an agricultural practice so reckless that they've decided it's better for their reputation to leave everything shrouded in doubt. It's much more obvious to me that China is concealing something than what they're concealing. (Of course, that's usually how concealing stuff works.)
That said, I still think zoonosis near Wuhan is unlikely. In a pre-pandemic publication with no incentive to lie, the WIV studied antibodies to SARS-like viruses in the blood of people living near bats in Yunnan province. They used blood from people living in Wuhan as a negative control:
> As a control, we also collected 240 serum samples from random blood donors in 2015 in Wuhan, Hubei Province more than 1000 km away from Jinning (Fig. 1A) and where inhabitants have a much lower likelihood of contact with bats due to its urban setting.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6178078/
So while it's possible that natural zoonosis did occur in Wuhan, I believe that would require the WIV staff to be genuinely mistaken.