This is one of the more reasonable trademark defenses by one of the "big guys" that I've seen - one they are required to defend in order to keep. So, though it hurts, you pick a new name and move on. Very possibly the lawyers told the CEO to not respond to those emails until a decision was made.
As an aside, the post starts by saying "it's not something to get worked up about" -- and then proceeds to do nearly exactly that, detailing even his email "exchange" with the CEO.