It's good he publicised this but the length of the post and how hard he tried to get a response leads me to think he cares. He should not care about petty, deranged people.
I know this conference is probably not using this particular blocklist, but why should a conference 1) use a blocklist and 2) block people just for being of particular political view?
At some point you offended the wrong person, they added you to one of those shared blocklists, and that's all, you're banned forever.
Who's to blame? I'd say you, for caring. This is the way politics works now, and some software projects have, for some reason, joined the politics battle. By caring you're giving them weight. Just flip them off, tell them to go fuck themselves, and keep thinking the way you do.
It's not worth it to give up on your views on politics just to not be ostracised by these manchilds and circus freaks. They live off attention; if you don't pay attention to them they die. Don't give them any legitimacy, because most of those who take these decisions don't even know how to code and they are there to hijack the projects with their politics.