a,b,c) The response to these grew so long that it was worth its own community post: History of the Fandom by:Foxhoarder
d) In my opinion the booru worked perfectly until posts started disappearing, but ultimately it was Guzziman’s incompetence and/or carelessness that ruined its reputation. Many users complained about the hostility - especially from anonymous posters - which was why it once had an option to disable anonymous comments from posts altogether. At some point the checkbox just disappeared, and Guzziman didn’t know how to enable it again.
But that was nothing compared to the disappearing comments, and later entire posts. First it was marked up as moderators being overeager to censor things, but when every post with Fluffycommissions tagged as artist disappeared, shit really hit the fan. It turned out there were old un-deactivated moderator accounts on the booru. Guzziman was banned for hacking - then unbanned when it was pointed out how anyone with hacking skills could easily spoof their IP address. But comments kept disappearing, and eventually Guzziman just shut down the booru altogether.
However, what turns this from a tragic tale of man over his head to one of malicious betrayal is that Guzziman closed the booru in the most destructive way he could. People had been offering help for him literally the same month, and he had assured them that everything was in order to keep the booru going for another year. If it wasn’t for a few cautious people creating archives of all the images there, 99% of all stories and pictures the fandom has ever produced would have been gone for good.