naming policy rules... what are they?

[JaVeDK]

"Character renaming can and will occur if a player’s name is offensive. (GM Discretion)"

This clearly states that it is up to the individual GM (and therefore assumingly by extension also guide) to decide what names they find offensive.

The definition of offensive according to Webster is something: "causing displeasure or resentment". If it is the aim of the server to preserve a fantasy environment (which would be logical since this is a fantasy game), then a name that obviously does not fit the setting can be considered offensive to that end.