Some people are.
Seriously, though, everybody can comment and raise questions, but the author is right to discourage wild speculation.
When somebody says, "Please stop" it's not like they're banning all future discussion. If you disagree he can't bar you from participating.
But you should give his answers some serious consideration. Compared to a lot of the wild speculation people get into, what he says does carry some weight.
I’m probably more of a skeptic than most. But I welcome anyone with any ideas about what might be going on here. No harm comes to anyone from free discussion, only from suppressing it.