"The most destructive people linked to conspiracy theories and denialism are those with academic appointments - and those who can manipulate their backgrounds to appear as if they have had academic appointments."
Why? Probably because they write are fluently and prolifically than the guy you meet at 2pm in the bar who can't stop going on about all of those people on Hillary Clinton's hit list. (Hey, if you're in the bar at 2pm, you're asking for it.)
But it's not just the unhinged ones - those of us who are sane generally don't see much point in confronting the crazies:
"Academics tend to avoid controversies concerning pseudohistory and pseudoscience because they can get roughed up and dragged into quagmires of circular debate."
You don't get promoted for batting down looney claims, and British libel law doesn't help either. Countering every mainstream expert statement with one from the lunatic fringe seems to be often be standard operating procedure in journalism.
Given this environment, I find it hard to blame to the academic community for allowing conspiracy theories to flourish.