Why is it against the forum rules to report a player, by his ingame name, of scamming or stealing

Here is the rule:

F. Harassment and Defamatory Statements
Anything construed as referring to other individuals or Trion Worlds employees using any disallowed content or behavior.

If Person X scams person Y in the game, why is person Y not allowed to write a post warning people not to have trades with X?