Or they might prefer their pal to come speak at the last few open entries, and Douglas got invited instead.
Or they might be idiots.
Or insane.
Or "professional" touchy-feelers....
"We have asked John Doe not to attend the party as we have heard word that many parents would not be comfortable having him around their children".
Claims nothing, insinuates obvious reputation destroying behavior.
The insinuation made in the actual example with Douglas Crawford isn't exactly this clear cut, but it is still very damaging while lacking documented basis in reality.
Clearer now?