>... is only going to add fuel to the conspiracy theories.
That's a bad thing only if the conspiracy theory is false. At this point, the theory that the Chinese Communistic Party conspired to cover up a lab leak is not implausible. There are multiple known occurrences of pathogens escaping from laboratories.
It would not be in the least surprising if this was a lab leak, and it is no more "harmful" to speculate that it was than to speculate that it was a wild virus.
Do you realise that this is very easily true for any company or office at that time of the year?
Does the US government "have reason to believe that several teachers in a high school in Milan became sick in autumn 2015 with symptoms consistent with both Covid and seasonal flu"? Yes, it does! Good job, US government!
Well that depends on your objective. If it's to push a certain narrative, then it's bad if it contradicts that narrative; whether or not it's true is secondary.