Its only recently that research labs could engineer these viruses. Only recently have you been able to engineer mice with human ACE2 receptors, and breed viruses in them. History is not what you base your conclusions on in 2020’s biochemistry.
It has been strongly asserted by the scientific community that Covid-19 bears no hallmarks of an engineered virus. In fact, no one in this thread is even suggested it was engineered. That's the whole point of the article. The "accidental leak" theory is being conflated with "engineered weapon theory". The only options on the table are "animal -> human" or "animal -> lab -> human". Both are plausible and we have no conclusive evidence one way or the other.
Engineering a virus, in the sense that you're talking about, is not what was meant. Allowing the virus to naturally mutate in an animal host, over thousands of generations, will get you to the same endpoint. This is gain of function research, the whole point is to find out if the virus could naturally evolve some feature you are interested in. Engineering it to do so would defeat the point.
This is not exactly accurate. But it’s easier to get to the full story if people accept the lab leak of an unmodified virus as a possibility. However, the “assertions” are misleading and have been debunked. The virus does appear to be chimeric. There is a missing link in both hypotheses, but the lab leak hypotheses offers a few possible explanations. The zoonotic hypothesis still doesn’t have an explanation for that part.