I think they were trying to identify any potential natural viruses in advance and one of the samples got out. While it would probably have reached the human population eventually, that fubar made it happen well before it would have under natural circumstances.
And like all authoritarian regimes, the initial response was to hide anything that might embarrass them rather than alert anyone else to the problem. At least not before it was a little too late.
None of this excuses Trump's incredibly poor response, since there were many things he could control but didn't, and even the one or two things he did right were not done completely and were undermined as a result.