Rules exist for selective enforcement, to allow a justifiable way to weed out undesirables.
Laws are little different. Just look at the number of celebrities serving time for their crimes, often the subject of extensive media coverage.
Look at politicians and see the same.
Its how society works.
Not to say it's good, just real.
The biased moderation thing comes up a lot as its a favourite of sub-species of forumite like the forum undead and the compulsory-pvp-types. However they tend to be more than a little angry about the game which means they chuck name calling into the mix far more frequently, so the bias is actually in the offending not the enforcement.