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.
That has not been established. Without knowing the author’s history or any background the only thing I can conclude from the conference’s organisers is that they are disorganised and with misplaced priorities: if a potential speaker alleges they’ve been incorrectly blacklisted (and shows no obvious warning signs) then investigating and rectifying the situation as necessary should be a high priority: that’s just good customer service and community leadership - especially as checking the pedigree of a Twitter blacklist is a trivial 5 minute task.
If the author really was unwelcome for some reason or another they would have ignored his email or replied with an short “because...” message - not a “we don’t care” response - because that really does mean they really don’t care.
(Though I’ll make a snark about how the JS community moves so fast that anything useful gleaned from a JS conf would be obsolete in a year’s time anyway - limiting the potential value of his attendance anyway)
They should be ostracized, shamed, fired and barred from employment. We should prevent hiring anybody who shows any sign of belonging to the PC-brigade. (Make no mistake - they are already doing this to their perceived "enemies", and not just based on opinions but even sex and ethnicity.)
We should make companies understand the incredible damage these people can cause.
Your post reads like fear-mongering of laughably incorrect activist-left stereotypes. This is HN, we can do better than that.