If I were to call you a name in game, and you report me, I would be dealt with rather quickly. The reason the same attention isn't paid to bot reports is because there is probably some policy to ignore said reports and stick with whatever internal means of looking for bot activity they have. For one of the most popular SUBSCRIPTION BASED mmorpgs out there, "its too hard" isn't a good excuse to at least attempt to prevent market breaking activities from happening.
The reason they put so much resources into policing language and negative behavior with regards to other players, is because people are more likely to respond to bad behavior like harassment with quitting the game.. which means less profit for them. Not enough people quit because of bots, so they don't really seem to care if an economy is wrecked.