Some ppl with the wrong proxies got punished for not changing it at the right time or they didn't even check to make sure their proxy was voting in their best interest.
If I remember right, the user you mention proxied Justyy, who ended up supporting the soc witnesses.
No, this is what happened (@mondoshawan shared the link):
https://peakd.com/steemworld/@steemchiller/my-accounts-are-on-the-hive-blacklist
Ah, well a few did get caught up in the way I explain above.
As for the blacklist, I think it is a bit petty, but unfortunately there's plenty of petty to go around these days. That pesky imperfect human nature at work.
Yes, plenty indeed :/