We've talked here on the site before about this issue -- the anonymity in online communities like World of Warcraft often leads to people throwing out offensive statements that they usually wouldn't in normal company. Most people shrug these off as just what happens in online games ("kids will be kids, and idiots will be idiots"), but this type of undercurrent behavior still signifies and perpetuates prejudices and hatreds that affect society at large.
The Gay and Lesbian Alliance Against Defamation (GLAAD) has recently started up a campaign to try and stamp out hatred and homophobia in communities like World of Warcraft, and they've published an op-ed on exactly why this is such a problem and what we can do to stop it. They don't mention WoW specifically, but we're one of the biggest online communities out there, and if nothing else, here's a chance to show just how tolerant we as a community can be.
The good news is that as the practice of online gaming grows, both players and policymakers are becoming more and more aware of the problem -- Microsoft met earlier this year with representatives from GLAAD to determine how better to combat offensive statements on Xbox Live, and the organization held a panel recently to discuss exactly this issue.