If the board were to have any influence they had to be able to do this. Whether this was the right time and the right issue to play their trump card I don't know - we still don't know what exactly happened - but I have a lot more respect for a group willing to take their shot than one that is so worried about losing their influence that they can never use it.
One wishes someone had pulled a similar (in sentiment) move on energy companies and arms suppliers.
Whether it was "smearing" or uncovering actual wrongdoing depends on the facts of the matter, which will hopefully emerge in due course. A board should absolutely be able and willing to fire the CEO, oust the chairman, and jeopardize supplier relationships if the circumstances warrant it. They're the board, that's what they're for!