Earlier quoted context omitted.
Ok, let's take that at face value. Are the unspecified others who would burn them down justified? At the end of the day, is there any positive moral case for this?
The others aren't burning them down, the others are making clear that they have conditions on participating, and if they're met, they're happy to do so. Triaging your project to get it done by excluding the one person who makes five others leave, by forcing the one guy out, is basic management. It's the basic stuff of editorial decisions. As for the larger case of "blacklisting", as Kunin describes it, the moral case…
Kunin opposed the idea of blacklisting in general, he didn't even endorse any person.
So now, for those who refuse to be published in the same magazine as him, the chain goes "unspecified other" -> Kunin didn't disavow -> they can't publish anything where Kunin might also publish? There's not even a specific idea they're condemning besides general open-mindedness.
What about if the magazine had allowed him to publish, and you had been in there as well? Would you deserve censure as the third link? After all, you shared a stage with someone, and god only knows how many stages they've shared with how many people.