While I don't agree with Peter's method of leaving, I understand the motivation.
A reviewer needs an extremely thick skin, but even then some barbs burrow deep. Taken individually, we audiophiles are generally a friendly, fair-minded, level-headed lot, albeit with tendency toward exactitude. As a collective, however, we can exhibit four-M behaviour: Malcontented Middle-Aged Male Misanthropes. That tendency toward exactitude swiftly turns captious and judgmental, especially when hiding behind a keyboard.
For my own part, there are a number of 'off limits' forums that I refuse to visit, because I don't think I deserve to die in a fire simply for holding down my job. Worse, in such places, you have no comeback, no right to object publicly. You are at best court jester, but more often a convenient combination of whipping boy and prick magnet.
Psychologically speaking, there is only so much of this a person can take before you either skulk off, storm out, or suck a tailpipe. How much one can take varies, but if Peter's departure is angry and bitter, perhaps it is time to reflect why he should feel so angry and bitter to effectively suicide himself like this.
There does seem to have been something of a change in direction here. This was a friendly forum of high-end debate and discussion, but now it seems to be increasingly littered with agenda-filled ranting. If the forum continues down this all-too-predictable story arc, it will end with four people holding two conflicting and extremely polarised views arguing with one another at every juncture. This is at first entertaining, but ultimately extremely frustrating for other members and it lets the air out of the tyres of the forum. Eventually, even the combatants tire of the combat, or more accurately move on to another forum with a bigger audience and do the same thing again, like a plague of locusts.