Earlier quoted context omitted.
No, absolutely reasonable. They say that multiple other speakers have stated that Crockford's "presence would make some speakers uncomfortable to the point where they refused to attend or speak." So they chose to prioritise them over him, something which they can totally do as organisers. Do they owe everyone a detailed explanation for that? I think not.
1) "owe" - as in some kind of contractual obligation? were I a ticket-holder or Mr. Crockford, I would speak of being owed something, but I think you are using a strange word for a privately-presented public-conference that has insinuated quite a LOT, actually, by such a provocative statement. This private organization presenting this public conference can, of course, refuse to divulge anything it wishes to. The sten…
Regarding the other meaning, I could only repeat myself: they state that some other speakers have big problems with Crockford, and that they chose them over him. I think it's totally ok for them to do that, even without providing more information.
In fact, it's totally conceivable that revealing more information could hurt more people, or the same people more, or Crockford himself, or all of this. I fail to see how it would "advance humanity" if they did such a thing.