Dude it's his duty as a representative of shareholders. Shareholders deserve to have all offers for the company heard, and all possible acquirers notified so that the shareholders get the best possible offer.
Boards focus on representing shareholders. CEOs do too, mostly, but I'd argue that focusing on providing value to customers, which will in turn better provide value for shareholders, should be the main focus, because big companies too often lose sight of what the hell it is they're doing that is actually of value.