To be fair in this instance, this is a wild story that does have all the hallmarks of a wacky conspiracy theory straight out of a Bond film. Some secret Chinese laboratory is doing some secret stuff with some super spreading disease and then whoops it gets leaked and shuts the entire world down.
Also keep in mind where the info was coming from in the US: it was being introduced by Trump. This is someone who regularly spouses countless baseless conspiracies whenever he needs some sort of ammunition to blame a group he doesn't like. There is plenty of fair reasons to not have believed this story.
It's not some secret Chinese laboratory. It's a well known institute, a pretty famouse one in fact. It's the place that identified the source of the 2003 sars pandemic.
Also keep in mind where the info was coming from in the US: it was being introduced by Trump. This is someone who regularly spouses countless baseless conspiracies whenever he needs some sort of ammunition to blame a group he doesn't like. There is plenty of fair reasons to not have believed this story.