Maybe it is healthy for society in the long run to have pockets of divergent belief. Most of the time it is groundless and fades away. Every so often it gains traction. If it is based in reality, we gain a better understanding. If it is misleading, it vitalizes a competing and more correct understanding.

The more interesting phenomenon is that we are able to agree on anything at all, it's not exactly our strongest instinct. Reading through HN, for example, the longest comment chains are a series of disagreements. But we build resources like Wikipedia and science journals, which also use disagreement as an engine for generating a more correct understanding. Its a strange and hopeful aspect of human societies.