Much work has been done on genetically engineering viruses and that includes coronoviruses. We certainly know very well how to do it for one purpose or another. This is a fact not a theory. Currently it's impossible to say Covid-19 resulted, maybe in part, from this activity or not. Terrible not to know something for a fact but that's how it is. Call a particular view a conspiracy theory if you like but that's just rhetoric and takes us not a step further towards a definitive answer.