Because everyone has their bouts of bias and it's useful to point it out. While fanboy is almost always a more extreme word meant to insult intelligence, motives, etc.
I'm pretty sure the word "bias" cannot be effectively used to insult someone anyway. Seriously, no matter how passionate "bias" is said, I can't see how anyone could feel offended. The quote you gave seemed relatively passive and certainly doesn't warrant moderation. And honestly, if a user feels hurt or offended from being called "biased", then there's a bigger problem that a mere moderation cannot heal.







