I've been talking with him through email, and when I asked him why he left P.SE he said:
"I left for the exact same reason you wrote on your P.SE profile."
(He also said it was OK to share his thoughts in an answer here, and that he's not going to bother posting an answer here because he's gone for good, but he's pretty sure everyone knows why he left)
As for my profile, well it's not very flattering because I wrote it one day while I was frustrated towards P.SE. My feelings haven't changed, but normally I would have kept them to myself
If someone makes a Q&A site for Programmers to ask questions and get
answers from other Programmers about any issue related to their career
choice or self-identity as a programmer, let me know. I'd love to
participate in such a site again, and will help you promote it.
As for this site, I'm done with it unless something changes. I feel
its changed too far from the original programming resource it once
was, and the current moderation style is not for me.
I dislike that so much valuable information gets deleted for the sake
of "maintaining a clean site", dislike the way many users are treated
(particularly new ones), and dislike the way the overall culture of
this site has been changing from a community of programmers out to
teach and learn from each other, to an insular group of programming
elitists (of course this isn't all of you, or probably even most of
you. Its just a large percentage of the more active/vocal users who
take part in running the site).
Anyways, I'm not interested in helping to support this site anymore,
although I will be happy to take part in any initiatives to changes
I hope the powers-that-be will take this into account when deciding future policies for a site, as Pierre is not the first one of our top users to quit the site. I can confirm that
DeveloperArt left for the same reason (been talking to him via email too), and I've seen many other high-rep names quietly disappear over time.
As to your 2nd question, yes it's possible to recover a deleted account although according to MSO it requires "Jeff-Level" access