To be clear, at no point in that letter did it say that Rafa was "perfectly happy". If he was "perfectly happy", surely contract talks would not be on hold?
The way I see it, the thing is designed to minimise negative reaction. More will come out and I am working on something myself. It is in the interests for those involved at the club to minimise fallout. Rafa won't want another relegation on his CV, Lascelles will learn from his current manager and in the future will surely gain more lucrative contracts.
In some cases it is worth reading between the lines. I can't speak for them but is the club more likely to be bought by a new owner if the support is seen as toxic? What would the effect be on player motivation?
The letter should be seen for what it is. We have been dumped on but, Ashley aside, we are going to make the best of a totally shite situation.