The problem is that large companies are made of lots of people, and some of those people might have awful opinions or say things that will get your business in trouble.
The larger you are and the more people that are communicating, the bigger the chance that someone says something terrible.
Particularly if you are a large public company and there may be legal requirements around specific parts of disclosure.
Besides, companies don't want their secret new feature announced before their competitors know about it, in a way that is poorly communicated and confuses customers, and then find that the person who announced it has a profile picture which is them at a far-right protest / far-left protest / made some sexist jokes / has a bio advertising their onlyfans account etc or a million other things that could be seen as against the corporate image.
The larger you are and the more people that are communicating, the bigger the chance that someone says something terrible.
Particularly if you are a large public company and there may be legal requirements around specific parts of disclosure.
Besides, companies don't want their secret new feature announced before their competitors know about it, in a way that is poorly communicated and confuses customers, and then find that the person who announced it has a profile picture which is them at a far-right protest / far-left protest / made some sexist jokes / has a bio advertising their onlyfans account etc or a million other things that could be seen as against the corporate image.