Why did Argon2 win the PHC?
I have been part of several cryptographic competitions (AES, eSTREAM, SHA-3, PHC). In every single one of them, some people worded bitter reproaches and wailed and whined about the unfairness of the selection process. It's just that people are like that, and being very good at cryptography does not prevent smart cryptographers from being basically people.

The mailing-list was hosted on Gmane, which was a free resource maintained by somebody on his spare time. In July 2016 he decided he had had enough of it (he was fed up with recurrent DoS attacks). The PHC mailing-list archives, though, were recovered and put back online by Alexander Peslyak (aka "Solar Designer", who was behind the yescrypt PHC candidate). You can see for instance the winner announcement there.