That's not the web's problem, that's a human being problem. Just look throughout history and you'll see examples of mindless nationalism, genocide, mafia, KKK, etc. What the web allows you to do is to be exposed to it all if you choose, and causes rifts between conflicting views that were already established. Before these close minded groups just never had to interact with each other, now they do. Those ideas ended up spreading to their communities ("gay people are ruining our culture!", or whatever). Those rifts just strengthen their original ideas and they hold on to them out of spite.The web's problem is it makes it so easy to find like-minded people so you can easily create a personalized stream of information that exists only to affirm your opinions.