This is not in any way fair, and furthermore not against the rules. If you set out to farm gold or items, the last thing you want to do is make that process longer or worse by reducing your gold gained/ item(s) gained per hour. Why it is unreasonable to simply avoid pvp is beyond me but Thari seems to think it is. Forcing players into unwanted pvp encounters is not within the spirit of the game, regardless of circumstance(s). Yes, we are playing on a pvp server. But playing on a pvp server does not mean you have to attack every player you see. This is not what a pvp server means, and it never was. (Druid truce across faction, anyone?)
As far as I can tell this type of behavior is neither against the rules nor is there ground for "punish(ment) in more severe ways". How a single GM can choose to apply unofficial rules to a very small percent of the playerbase is atleast in my eyes a good sign that your current gamemaster infrastructure is atleast to some degree flawed. For the record, this wasn't against the rules on nostalrius, as far as I can tell it isn't against the rules here either according to anyone but Thari and it wasn't against the ToS back in the old live vanilla WoW days.