The WT is a cult.
A formal organization to expose the WT is just another cult.... an anti-WT cult.
XJWs have no desire to trade one cult for another.
Grass root efforts such as this letter writing is the way to go IMO. Anyone can get involved who wants to. We each can give of our time and resources freely, without having a corporate structure bogging things down, then abuse you when you don't follow the party line.
The power of many great minds can come together for colaberation that is just not possible with a corporate cult.