As makers and participants in internet culture, I think it's incumbent on all of us to find ways to minimize the downsides of anonymity and pseudonymity while maximizing the benefits. Because otherwise, the baby's getting thrown out with the bathwater.
Note, for example, that Facebook doesn't allow any anonymity, and Quora only allows it with tight controls. I think the long-term trend is to get rid of it, which would be a shame.
Sure, some people are fine being ignorant bigots in the town square at high noon, too. But that doesn't mean that people are equally comfortable being bigots no matter the circumstance. And even if the amount of bigotry were identical whether anonymous or not, it doesn't mean that people won't perceive anonymity as the problem because of the broken social feedback loop.
That said, I think anonymity actually is an enabler here. The KKK knew exactly what they were doing with those hoods.
Note, for example, that Facebook doesn't allow any anonymity, and Quora only allows it with tight controls. I think the long-term trend is to get rid of it, which would be a shame.