I understand where he is coming from – when a company is potentially for sale it has to often be confidential in the early stages especially if you are privy to a lot of confidential information that goes hand in hand with that particular company.
In addition this site may have a number of employees that aren’t at this early stage aware of the sale….
There could be all sorts of reasons for his motivations which I am not going to guess at but I am sure (hope) they are valid